docs: (WIP) Getting Started Documentation Page

[viglucci]

Work In Progress.

Progress on adding a "Getting Started" documentation page, following a rough outline (open to feedback/change):

• TOC
• Getting Started vanilla RSocket
  • Dependencies (JS, JAVA, CPP, Kotlin, Go, Rust, Python, Ruby)
  • Connector example (WS) + Server Example (WS) with some minimalist requestResponse
  • Working with Payload (data | metadata)
  • Composite Metadata
  • Routing your request
  • Tracing
  • Auth Metadata
• Getting Started with RSocket RPC
• Setup dependencies
• Code generation
• Reactive API
  • Flowable
  • Single
  • Project Reactor
• Tutorials (in Action)
  • Chat App (Authentication, Routing, RPC)
  • Frontend (React/Angular/etc.)

Live preview: https://deploy-preview-29--rsocket.netlify.app/docs/getting-started

---

Open question for @OlegDokuka and other rsocket-java contributors concerning rsocket-java examples for constructing an RSocketConnector:

Some examples demonstrate the .connectWith(transport) API and others demmonstrate RSocketClient.from(source). Do we prefer one of the other for code examples?

WebsocketClientTransport ws = WebsocketClientTransport.create(
  URI.create("ws://rsocket-demo.herokuapp.com/ws"));

RSocket clientRSocket = RSocketConnector
  .connectWith(ws)
  .block();

compared to:

Mono<RSocket> source =  RSocketConnector.create()
 .metadataMimeType("message/x.rsocket.composite-metadata.v0")
 .dataMimeType("application/json")
 .connect(TcpClientTransport.create("localhost", 7000));

RSocket clientRSocket = RSocketClient.from(source);