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/app/v2beta/query.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"strings"
 
+	"connectrpc.com/connect"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
 	"github.com/zitadel/zitadel/internal/api/grpc/app/v2beta/convert"
@@ -12,19 +13,19 @@ import (
 	app "github.com/zitadel/zitadel/pkg/grpc/app/v2beta"
 )
 
-func (s *Server) GetApplication(ctx context.Context, req *app.GetApplicationRequest) (*app.GetApplicationResponse, error) {
-	res, err := s.query.AppByIDWithPermission(ctx, req.GetId(), false, s.checkPermission)
+func (s *Server) GetApplication(ctx context.Context, req *connect.Request[app.GetApplicationRequest]) (*connect.Response[app.GetApplicationResponse], error) {
+	res, err := s.query.AppByIDWithPermission(ctx, req.Msg.GetId(), false, s.checkPermission)
 	if err != nil {
 		return nil, err
 	}
 
-	return &app.GetApplicationResponse{
+	return connect.NewResponse(&app.GetApplicationResponse{
 		App: convert.AppToPb(res),
-	}, nil
+	}), nil
 }
 
-func (s *Server) ListApplications(ctx context.Context, req *app.ListApplicationsRequest) (*app.ListApplicationsResponse, error) {
-	queries, err := convert.ListApplicationsRequestToModel(s.systemDefaults, req)
+func (s *Server) ListApplications(ctx context.Context, req *connect.Request[app.ListApplicationsRequest]) (*connect.Response[app.ListApplicationsResponse], error) {
+	queries, err := convert.ListApplicationsRequestToModel(s.systemDefaults, req.Msg)
 	if err != nil {
 		return nil, err
 	}
@@ -34,32 +35,32 @@ func (s *Server) ListApplications(ctx context.Context, req *app.ListApplications
 		return nil, err
 	}
 
-	return &app.ListApplicationsResponse{
+	return connect.NewResponse(&app.ListApplicationsResponse{
 		Applications: convert.AppsToPb(res.Apps),
 		Pagination:   filter.QueryToPaginationPb(queries.SearchRequest, res.SearchResponse),
-	}, nil
+	}), nil
 }
 
-func (s *Server) GetApplicationKey(ctx context.Context, req *app.GetApplicationKeyRequest) (*app.GetApplicationKeyResponse, error) {
-	queries, err := convert.GetApplicationKeyQueriesRequestToDomain(req.GetOrganizationId(), req.GetProjectId(), req.GetApplicationId())
+func (s *Server) GetApplicationKey(ctx context.Context, req *connect.Request[app.GetApplicationKeyRequest]) (*connect.Response[app.GetApplicationKeyResponse], error) {
+	queries, err := convert.GetApplicationKeyQueriesRequestToDomain(req.Msg.GetOrganizationId(), req.Msg.GetProjectId(), req.Msg.GetApplicationId())
 	if err != nil {
 		return nil, err
 	}
 
-	key, err := s.query.GetAuthNKeyByIDWithPermission(ctx, true, strings.TrimSpace(req.GetId()), s.checkPermission, queries...)
+	key, err := s.query.GetAuthNKeyByIDWithPermission(ctx, true, strings.TrimSpace(req.Msg.GetId()), s.checkPermission, queries...)
 	if err != nil {
 		return nil, err
 	}
 
-	return &app.GetApplicationKeyResponse{
+	return connect.NewResponse(&app.GetApplicationKeyResponse{
 		Id:             key.ID,
 		CreationDate:   timestamppb.New(key.CreationDate),
 		ExpirationDate: timestamppb.New(key.Expiration),
-	}, nil
+	}), nil
 }
 
-func (s *Server) ListApplicationKeys(ctx context.Context, req *app.ListApplicationKeysRequest) (*app.ListApplicationKeysResponse, error) {
-	queries, err := convert.ListApplicationKeysRequestToDomain(s.systemDefaults, req)
+func (s *Server) ListApplicationKeys(ctx context.Context, req *connect.Request[app.ListApplicationKeysRequest]) (*connect.Response[app.ListApplicationKeysResponse], error) {
+	queries, err := convert.ListApplicationKeysRequestToDomain(s.systemDefaults, req.Msg)
 	if err != nil {
 		return nil, err
 	}
@@ -69,8 +70,8 @@ func (s *Server) ListApplicationKeys(ctx context.Context, req *app.ListApplicati
 		return nil, err
 	}
 
-	return &app.ListApplicationKeysResponse{
+	return connect.NewResponse(&app.ListApplicationKeysResponse{
 		Keys:       convert.ApplicationKeysToPb(res.AuthNKeys),
 		Pagination: filter.QueryToPaginationPb(queries.SearchRequest, res.SearchResponse),
-	}, nil
+	}), nil
 }