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/protoc/protoc-gen-zitadel/zitadel.pb.go.tmpl

@@ -5,6 +5,7 @@ package {{.GoPackageName}}
 import (
 	"github.com/zitadel/zitadel/internal/api/authz"
 	{{if .AuthContext}}"github.com/zitadel/zitadel/internal/api/grpc/server/middleware"{{end}}
+	{{if .AuthContext}}"github.com/zitadel/zitadel/internal/api/grpc/server/connect_middleware"{{end}}
 )
 
 var {{.ServiceName}}_AuthMethods = authz.MethodMapping {
@@ -23,6 +24,13 @@ func (r *{{ $m.Name }}) OrganizationFromRequest() *middleware.Organization {
 		Domain: r{{$m.OrgMethod}}.GetOrgDomain(),
 	}
 }
+
+func (r *{{ $m.Name }}) OrganizationFromRequestConnect() *connect_middleware.Organization {
+	return &connect_middleware.Organization{
+		ID: r{{$m.OrgMethod}}.GetOrgId(),
+		Domain: r{{$m.OrgMethod}}.GetOrgDomain(),
+	}
+}
 {{ end }}
 
 {{ range $resp := .CustomHTTPResponses}}