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/user/v2/totp.go

@@ -3,42 +3,44 @@ package user
 import (
 	"context"
 
+	"connectrpc.com/connect"
+
 	"github.com/zitadel/zitadel/internal/api/grpc/object/v2"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/pkg/grpc/user/v2"
 )
 
-func (s *Server) RegisterTOTP(ctx context.Context, req *user.RegisterTOTPRequest) (*user.RegisterTOTPResponse, error) {
+func (s *Server) RegisterTOTP(ctx context.Context, req *connect.Request[user.RegisterTOTPRequest]) (*connect.Response[user.RegisterTOTPResponse], error) {
 	return totpDetailsToPb(
-		s.command.AddUserTOTP(ctx, req.GetUserId(), ""),
+		s.command.AddUserTOTP(ctx, req.Msg.GetUserId(), ""),
 	)
 }
 
-func totpDetailsToPb(totp *domain.TOTP, err error) (*user.RegisterTOTPResponse, error) {
+func totpDetailsToPb(totp *domain.TOTP, err error) (*connect.Response[user.RegisterTOTPResponse], error) {
 	if err != nil {
 		return nil, err
 	}
-	return &user.RegisterTOTPResponse{
+	return connect.NewResponse(&user.RegisterTOTPResponse{
 		Details: object.DomainToDetailsPb(totp.ObjectDetails),
 		Uri:     totp.URI,
 		Secret:  totp.Secret,
-	}, nil
+	}), nil
 }
 
-func (s *Server) VerifyTOTPRegistration(ctx context.Context, req *user.VerifyTOTPRegistrationRequest) (*user.VerifyTOTPRegistrationResponse, error) {
-	objectDetails, err := s.command.CheckUserTOTP(ctx, req.GetUserId(), req.GetCode(), "")
+func (s *Server) VerifyTOTPRegistration(ctx context.Context, req *connect.Request[user.VerifyTOTPRegistrationRequest]) (*connect.Response[user.VerifyTOTPRegistrationResponse], error) {
+	objectDetails, err := s.command.CheckUserTOTP(ctx, req.Msg.GetUserId(), req.Msg.GetCode(), "")
 	if err != nil {
 		return nil, err
 	}
-	return &user.VerifyTOTPRegistrationResponse{
+	return connect.NewResponse(&user.VerifyTOTPRegistrationResponse{
 		Details: object.DomainToDetailsPb(objectDetails),
-	}, nil
+	}), nil
 }
 
-func (s *Server) RemoveTOTP(ctx context.Context, req *user.RemoveTOTPRequest) (*user.RemoveTOTPResponse, error) {
-	objectDetails, err := s.command.HumanRemoveTOTP(ctx, req.GetUserId(), "")
+func (s *Server) RemoveTOTP(ctx context.Context, req *connect.Request[user.RemoveTOTPRequest]) (*connect.Response[user.RemoveTOTPResponse], error) {
+	objectDetails, err := s.command.HumanRemoveTOTP(ctx, req.Msg.GetUserId(), "")
 	if err != nil {
 		return nil, err
 	}
-	return &user.RemoveTOTPResponse{Details: object.DomainToDetailsPb(objectDetails)}, nil
+	return connect.NewResponse(&user.RemoveTOTPResponse{Details: object.DomainToDetailsPb(objectDetails)}), nil
 }