Replace IUser.AvatarUrl with IUser#GetAvatarUrl(size)

This is to support the new user image endpoint, which provides a parameter for image resizing.

Conflicts:
	docs/guides/samples/dependency_module.cs
	src/Discord.Net.Commands/Utilities/ReflectionUtils.cs

Enhance Dependency Injection

Conflicts:
	docs/guides/samples/logging.cs
Update logging.cs

Update home page on docs

Update doc samples

Update docs' status sample

Add Roles property to SocketGuildUser

Typo

Fixed couple non-default arguments in REST messages

Fix ParameterInfo.Type sometimes being null

there's a few different ways to select a user's roles from their role IDs, and this one seems to be the most efficient.

doesn't seem like there's any reason this shouldn't be included.

SetStatus and SetGame don't exist, only SetStatusAsync and SetGameAsync

Throw an InvalidOp if a user tries to set the DefaultRunMode to Default

never overestimate the end user

this should be handled by #520

Add BeforeExecute/AfterExecute methods to ModuleBase