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/settings/v2/settings.go

@@ -3,25 +3,27 @@ package settings
 import (
 	"context"
 
+	"connectrpc.com/connect"
+
 	"github.com/zitadel/zitadel/internal/api/grpc/object/v2"
 	"github.com/zitadel/zitadel/pkg/grpc/settings/v2"
 )
 
-func (s *Server) SetSecuritySettings(ctx context.Context, req *settings.SetSecuritySettingsRequest) (*settings.SetSecuritySettingsResponse, error) {
-	details, err := s.command.SetSecurityPolicy(ctx, securitySettingsToCommand(req))
+func (s *Server) SetSecuritySettings(ctx context.Context, req *connect.Request[settings.SetSecuritySettingsRequest]) (*connect.Response[settings.SetSecuritySettingsResponse], error) {
+	details, err := s.command.SetSecurityPolicy(ctx, securitySettingsToCommand(req.Msg))
 	if err != nil {
 		return nil, err
 	}
-	return &settings.SetSecuritySettingsResponse{
+	return connect.NewResponse(&settings.SetSecuritySettingsResponse{
 		Details: object.DomainToDetailsPb(details),
-	}, nil
+	}), nil
 }
 
-func (s *Server) SetHostedLoginTranslation(ctx context.Context, req *settings.SetHostedLoginTranslationRequest) (*settings.SetHostedLoginTranslationResponse, error) {
-	res, err := s.command.SetHostedLoginTranslation(ctx, req)
+func (s *Server) SetHostedLoginTranslation(ctx context.Context, req *connect.Request[settings.SetHostedLoginTranslationRequest]) (*connect.Response[settings.SetHostedLoginTranslationResponse], error) {
+	res, err := s.command.SetHostedLoginTranslation(ctx, req.Msg)
 	if err != nil {
 		return nil, err
 	}
 
-	return res, nil
+	return connect.NewResponse(res), nil
 }