refactor(*): update RPC

[NotSugden]

This PR removes and changes alot of the RPC functions as they have been (presumably) removed, or the API has changed (docs reference)

resolves #71
resolves #76

This is most definetly a semver: major change, version has been bumped to 4.0.0
This PR will be a draft for the time being, there are still some things that need tweaking slightly

A full list of changes

• Version bumped to 4.0.0
• Added typings
  • Added typescript^4.0.2 as a dev-dependency
• Added/Updated all JSDoc documentation
• Changed RPCClient#accessToken to non-enurmerable
• Added RPCClient#config as a private object
  • Added RPCClient#apiURL as a public getter
  • Added RPCClient#cdnURL as a public getter
• Refactored RPCClient#fetch
  • It is no longer set in the constructor
  • The path parameter has been changed to longer require a leading /
  • It is now an async function
• Refactored RPCClient#connect
  • Gave it a general refactor
  • Added a capital C to the closed connection error
• Changed parmeter names of RPCClient#request
  • cmd to command
  • evt to event
• Added private method RPCClient#_onRpcClose to handle rpc close
• Refactored RPCClient#_onRpcMessage
  • Destructured the message parameter
• Removed RPCClient#_subscriptions
  • Removed in favour of a better subscription handler
• Refactored RPCClient#authorize
  • Re-ordered destructured parameters
• Refactored RPCClient#authorize to be an async function
• Refactored all RPCClient#get* functions to be async
  • Refactored getChannel, getChannels, getGuild, getUser to use new Channel, and Guild structures respectively
• Added new structures
  • Guild
  • Channel
  • User
  • UserFlags
  • ClientApplication
• Refactored some functions to have no return value (void) and be async
  • RPCClient#setCertifiedDevices
  • RPCClient#setActivity
  • RPCClient#clearActivity
  • RPCClient#sendJoinInvite
• RPCClient#closeJoinRequest
• Removed RPCClient#sendJoinRequest as it doesn't seem to be documented anymore - not sure on that so if someone could confirm that
• Refactored RPCClient#setUserVoiceSettings to use less lines
• Refactored RPCClient#select* to be async and use the new Channel structure
  • RPCClient#selectTextChannel no longer has a force parameter, as its no longer effected
  • RPCClient#selectTextChannel no longer takes an object as its second parameter
• RPCClient#getVoiceSettings and RPCClient#setVoiceSettings use a private function to resolve the data returned by the RPC API
• Refactored RPCClient#captureShortcut
  • Now returns a promise which resolves with the first parameter to the callback function passed in the callback!
    • A bit funky I know, perhaps this needs another refactor?
• Refactored RPCClient#setActivity (general refactor)
• Removed undocumented (possibly removed?) functions
  • RPCClient#createLobby
  • RPCClient#updateLobby
  • RPCClient#deleteLobby
  • RPCClient#connectToLobby
  • RPCClient#sendToLobby
  • RPCClient#disconnectFromLobby
  • RPCClient#getLobbyMember
  • RPCClient#getRelationships
• Refactored RPCClient#subscribe
  • No longer uses RPCClient#_subscriptions and instead attaches an event listener
  • All events now emit its RPCEvent on the client
  • Returns a function to unsubscribe, rather than object with a single key unsubscrbibe
  • Is now async
• RPCClient#destroy is no longer async
• Removed undocumented events and commands from Constants (see diff for full list)
  • Re-ordered events and commands alphabetically
• Added API_BASE_URL, CDN_URL, UserFlags, and ChannelTypes into constants
• Removed undocumented RPC Errors codes and re-organized them
• Removed now-unused constants
  • LobbyTypes
  • RelationshipTypes
• Changed IPCTransport to emit an error on the client if it encounters an (what would've been) an unhandled promise rejection
• Removed the 2nd parameter for new Websocket(...) in WebSocketTransport, intellisense showed that it wasnt the correct type? can't test this due to whitelist-only feature
• Updated test
  • Renamed test to rpc.js
  • General refactor

[papaia]

yes

[devsnek]

You need to separate this into multiple PRs. Also remove the TS stuff, I won't maintain it. Use the @types system instead.