New app.server app.client app.persistence high-level wrappers

[synopse]

Define some high-level wrapper classes to easily generate client/server SOA code, with direct and proper usage of HTTP/WebSockets client/server classes, and proper association with TRestServer. Those units could be associated with app.daemon for direct easy hosting of server applications with app.server + app.persistence. For instance, a SOA server should be defined as TRestServerFullMemory with no table published. May also ease authentication using JWT or simple login credentials, depending of a Service-To-Service or Service-To-User login. For the app.persistence file, we should be able to add easily define a stand-alone MicroService persistence with SQLite3 and ORM, or access an existing SQL remote DB with either the ORM or (probably existing) SQL requests.