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/session/v2/query.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"time"
 
+	"connectrpc.com/connect"
 	"github.com/muhlemmer/gu"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
@@ -26,18 +27,18 @@ var (
 	}
 )
 
-func (s *Server) GetSession(ctx context.Context, req *session.GetSessionRequest) (*session.GetSessionResponse, error) {
-	res, err := s.query.SessionByID(ctx, true, req.GetSessionId(), req.GetSessionToken(), s.checkPermission)
+func (s *Server) GetSession(ctx context.Context, req *connect.Request[session.GetSessionRequest]) (*connect.Response[session.GetSessionResponse], error) {
+	res, err := s.query.SessionByID(ctx, true, req.Msg.GetSessionId(), req.Msg.GetSessionToken(), s.checkPermission)
 	if err != nil {
 		return nil, err
 	}
-	return &session.GetSessionResponse{
+	return connect.NewResponse(&session.GetSessionResponse{
 		Session: sessionToPb(res),
-	}, nil
+	}), nil
 }
 
-func (s *Server) ListSessions(ctx context.Context, req *session.ListSessionsRequest) (*session.ListSessionsResponse, error) {
-	queries, err := listSessionsRequestToQuery(ctx, req)
+func (s *Server) ListSessions(ctx context.Context, req *connect.Request[session.ListSessionsRequest]) (*connect.Response[session.ListSessionsResponse], error) {
+	queries, err := listSessionsRequestToQuery(ctx, req.Msg)
 	if err != nil {
 		return nil, err
 	}
@@ -45,10 +46,10 @@ func (s *Server) ListSessions(ctx context.Context, req *session.ListSessionsRequ
 	if err != nil {
 		return nil, err
 	}
-	return &session.ListSessionsResponse{
+	return connect.NewResponse(&session.ListSessionsResponse{
 		Details:  object.ToListDetails(sessions.SearchResponse),
 		Sessions: sessionsToPb(sessions.Sessions),
-	}, nil
+	}), nil
 }
 
 func listSessionsRequestToQuery(ctx context.Context, req *session.ListSessionsRequest) (*query.SessionsSearchQueries, error) {