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/secret.go

@@ -3,37 +3,38 @@ package user
 import (
 	"context"
 
+	"connectrpc.com/connect"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
 	"github.com/zitadel/zitadel/internal/command"
 	"github.com/zitadel/zitadel/pkg/grpc/user/v2"
 )
 
-func (s *Server) AddSecret(ctx context.Context, req *user.AddSecretRequest) (*user.AddSecretResponse, error) {
+func (s *Server) AddSecret(ctx context.Context, req *connect.Request[user.AddSecretRequest]) (*connect.Response[user.AddSecretResponse], error) {
 	newSecret := &command.GenerateMachineSecret{
 		PermissionCheck: s.command.NewPermissionCheckUserWrite(ctx),
 	}
-	details, err := s.command.GenerateMachineSecret(ctx, req.UserId, "", newSecret)
+	details, err := s.command.GenerateMachineSecret(ctx, req.Msg.GetUserId(), "", newSecret)
 	if err != nil {
 		return nil, err
 	}
-	return &user.AddSecretResponse{
+	return connect.NewResponse(&user.AddSecretResponse{
 		CreationDate: timestamppb.New(details.EventDate),
 		ClientSecret: newSecret.ClientSecret,
-	}, nil
+	}), nil
 }
 
-func (s *Server) RemoveSecret(ctx context.Context, req *user.RemoveSecretRequest) (*user.RemoveSecretResponse, error) {
+func (s *Server) RemoveSecret(ctx context.Context, req *connect.Request[user.RemoveSecretRequest]) (*connect.Response[user.RemoveSecretResponse], error) {
 	details, err := s.command.RemoveMachineSecret(
 		ctx,
-		req.UserId,
+		req.Msg.GetUserId(),
 		"",
 		s.command.NewPermissionCheckUserWrite(ctx),
 	)
 	if err != nil {
 		return nil, err
 	}
-	return &user.RemoveSecretResponse{
+	return connect.NewResponse(&user.RemoveSecretResponse{
 		DeletionDate: timestamppb.New(details.EventDate),
-	}, nil
+	}), nil
 }