Implement help command

[SunflowerFuchs]

We need a help command.
It should probably look like this:

help [function]

Without a parameter, it lists all (currently available) commands.
With a parameter, it returns extended information for the given command, if available.

[SunflowerFuchs]

First idea in terms of implementation right now:

• BasePlugin receives the following 3 functions:
  • public function canUseFunction(User $user, string $function) : bool {}
    • Returns whether the given function can be executed by the current user (see Implement bot command permission system #4).
    • If not implemented, defaults to true.
  • public function getHelpTexts() : string[] {}
    • Returns an array of strings, in the form of ['functionName' => 'This is the short help text']
  • public function getExtendedHelpText(string $function) : string {}
    • Returns a more detailed descriptions of the given function
    • If not implemented, falls back to the text from getHelpTexts for that function

Possible problems with this approach:

• Doesn't allow help texts for plugins without commands
• Not sure if getHelpTexts should instead just be a property