websocket server

[austinmilt]

This PR adds a base websocket server implementation, to be used for two-way JSON-based communication with clients in both event broadcasting and request/response messaging, such as to send commands to the emulator. The implementation is meant to stand alongside the existing SocketServer (more performant, lower-level, less dev friendly) and the websocket "server" (renamed to WebSocketClient) which is actually a client implementation for connecting to and sending messages to external websocket servers.

Some notes on the implementation:

• It uses a single channel for all communications and differentiates messages by a topic ID enum in request/response message wrappers. The primary advantage with this implementation is clients get the send/receive to/from a single URL.
• The message wrappers use composition for topic-specific messages (i.e. the registration-specific message lives under the registration field of the wrapper). The primary advantage here is that clients can use a single implementation to serialize/deserialize all messages in a single pass over the JSON.
• Clients may be registered for topics by registration requests or by force (for e.g. the error and registration topics).
• Being registered for a topic does not preclude a request message being handled, e.g. a client can send an echo request without getting it echoed back.
• Topics can be broadcast - goes to all clients registered for that topic - or client-specific - goes to a specific client based on some other message filtering or request/response. The implementation here does not use any broadcast topics. Those can be added in future topics.

Main Changes

• renamed the prior WebSocketServer to WebSocketClient to match its usage, and make room for the new websocket server added here (WebSocketClient, CommApi)
• added a websocket server implementation as described above including client registration and generic methods for messaging clients (WebSocketServer)
• added messages for three topics - topic registration (Registration.cs), echo for debugging (Echo.cs), and generic errors (Error.cs) - which are wrapped in wrappers described above (MessageWrapper.cs) and described by their topic enum (MessageWrapper).
• added CLI args for creating the websocket server (ArgParser, IMainFormForApi, ParsedCLIFlags, MainForm, CommApi) and use these to initialize the server (MainForm)

Check if completed:

• I have run any relevant test suites
• I, the committer, have read the licensing terms for contributors (last updated 2024-06-22) and am compliant

[austinmilt]

Would appreciate advice on how to properly do logging (both debug and otherwise)

[austinmilt]

Would appreciate advice here