feat: exchange gRPC server implementation to connectRPC (#10145)

# Which Problems Are Solved

The current maintained gRPC server in combination with a REST (grpc)
gateway is getting harder and harder to maintain. Additionally, there
have been and still are issues with supporting / displaying `oneOf`s
correctly.
We therefore decided to exchange the server implementation to
connectRPC, which apart from supporting connect as protocol, also also
"standard" gRCP clients as well as HTTP/1.1 / rest like clients, e.g.
curl directly call the server without any additional gateway.

# How the Problems Are Solved

- All v2 services are moved to connectRPC implementation. (v1 services
are still served as pure grpc servers)
- All gRPC server interceptors were migrated / copied to a corresponding
connectRPC interceptor.
- API.ListGrpcServices and API. ListGrpcMethods were changed to include
the connect services and endpoints.
- gRPC server reflection was changed to a `StaticReflector` using the
`ListGrpcServices` list.
- The `grpc.Server` interfaces was split into different combinations to
be able to handle the different cases (grpc server and prefixed gateway,
connect server with grpc gateway, connect server only, ...)
- Docs of services serving connectRPC only with no additional gateway
(instance, webkey, project, app, org v2 beta) are changed to expose that
- since the plugin is not yet available on buf, we download it using
`postinstall` hook of the docs

# Additional Changes

- WebKey service is added as v2 service (in addition to the current
v2beta)

# Additional Context

closes #9483

---------

Co-authored-by: Elio Bischof <elio@zitadel.com>

internal/api/grpc/project/v2beta/query.go

@@ -3,6 +3,7 @@ package project
 import (
 	"context"
 
+	"connectrpc.com/connect"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
 	filter "github.com/zitadel/zitadel/internal/api/grpc/filter/v2beta"
@@ -13,18 +14,18 @@ import (
 	project_pb "github.com/zitadel/zitadel/pkg/grpc/project/v2beta"
 )
 
-func (s *Server) GetProject(ctx context.Context, req *project_pb.GetProjectRequest) (*project_pb.GetProjectResponse, error) {
-	project, err := s.query.GetProjectByIDWithPermission(ctx, true, req.Id, s.checkPermission)
+func (s *Server) GetProject(ctx context.Context, req *connect.Request[project_pb.GetProjectRequest]) (*connect.Response[project_pb.GetProjectResponse], error) {
+	project, err := s.query.GetProjectByIDWithPermission(ctx, true, req.Msg.GetId(), s.checkPermission)
 	if err != nil {
 		return nil, err
 	}
-	return &project_pb.GetProjectResponse{
+	return connect.NewResponse(&project_pb.GetProjectResponse{
 		Project: projectToPb(project),
-	}, nil
+	}), nil
 }
 
-func (s *Server) ListProjects(ctx context.Context, req *project_pb.ListProjectsRequest) (*project_pb.ListProjectsResponse, error) {
-	queries, err := s.listProjectRequestToModel(req)
+func (s *Server) ListProjects(ctx context.Context, req *connect.Request[project_pb.ListProjectsRequest]) (*connect.Response[project_pb.ListProjectsResponse], error) {
+	queries, err := s.listProjectRequestToModel(req.Msg)
 	if err != nil {
 		return nil, err
 	}
@@ -32,10 +33,10 @@ func (s *Server) ListProjects(ctx context.Context, req *project_pb.ListProjectsR
 	if err != nil {
 		return nil, err
 	}
-	return &project_pb.ListProjectsResponse{
+	return connect.NewResponse(&project_pb.ListProjectsResponse{
 		Projects:   grantedProjectsToPb(resp.GrantedProjects),
 		Pagination: filter.QueryToPaginationPb(queries.SearchRequest, resp.SearchResponse),
-	}, nil
+	}), nil
 }
 
 func (s *Server) listProjectRequestToModel(req *project_pb.ListProjectsRequest) (*query.ProjectAndGrantedProjectSearchQueries, error) {
@@ -213,8 +214,8 @@ func privateLabelingSettingToPb(setting domain.PrivateLabelingSetting) project_p
 	}
 }
 
-func (s *Server) ListProjectGrants(ctx context.Context, req *project_pb.ListProjectGrantsRequest) (*project_pb.ListProjectGrantsResponse, error) {
-	queries, err := s.listProjectGrantsRequestToModel(req)
+func (s *Server) ListProjectGrants(ctx context.Context, req *connect.Request[project_pb.ListProjectGrantsRequest]) (*connect.Response[project_pb.ListProjectGrantsResponse], error) {
+	queries, err := s.listProjectGrantsRequestToModel(req.Msg)
 	if err != nil {
 		return nil, err
 	}
@@ -222,10 +223,10 @@ func (s *Server) ListProjectGrants(ctx context.Context, req *project_pb.ListProj
 	if err != nil {
 		return nil, err
 	}
-	return &project_pb.ListProjectGrantsResponse{
+	return connect.NewResponse(&project_pb.ListProjectGrantsResponse{
 		ProjectGrants: projectGrantsToPb(resp.ProjectGrants),
 		Pagination:    filter.QueryToPaginationPb(queries.SearchRequest, resp.SearchResponse),
-	}, nil
+	}), nil
 }
 
 func (s *Server) listProjectGrantsRequestToModel(req *project_pb.ListProjectGrantsRequest) (*query.ProjectGrantSearchQueries, error) {
@@ -329,12 +330,12 @@ func projectGrantStateToPb(state domain.ProjectGrantState) project_pb.ProjectGra
 	}
 }
 
-func (s *Server) ListProjectRoles(ctx context.Context, req *project_pb.ListProjectRolesRequest) (*project_pb.ListProjectRolesResponse, error) {
-	queries, err := s.listProjectRolesRequestToModel(req)
+func (s *Server) ListProjectRoles(ctx context.Context, req *connect.Request[project_pb.ListProjectRolesRequest]) (*connect.Response[project_pb.ListProjectRolesResponse], error) {
+	queries, err := s.listProjectRolesRequestToModel(req.Msg)
 	if err != nil {
 		return nil, err
 	}
-	err = queries.AppendProjectIDQuery(req.ProjectId)
+	err = queries.AppendProjectIDQuery(req.Msg.GetProjectId())
 	if err != nil {
 		return nil, err
 	}
@@ -342,10 +343,10 @@ func (s *Server) ListProjectRoles(ctx context.Context, req *project_pb.ListProje
 	if err != nil {
 		return nil, err
 	}
-	return &project_pb.ListProjectRolesResponse{
+	return connect.NewResponse(&project_pb.ListProjectRolesResponse{
 		ProjectRoles: roleViewsToPb(roles.ProjectRoles),
 		Pagination:   filter.QueryToPaginationPb(queries.SearchRequest, roles.SearchResponse),
-	}, nil
+	}), nil
 }
 
 func (s *Server) listProjectRolesRequestToModel(req *project_pb.ListProjectRolesRequest) (*query.ProjectRoleSearchQueries, error) {