Use References in Requests Where Possible

[Nerixyz]

Currently, most request structs use owned types for the request. However, they only need to serialize the request, thus they only need immutable references to the data.

Take the GetUsersRequest as an example:

twitch_api/src/helix/endpoints/users/get_users.rs

Lines 48 to 55 in 607b9ae

	pub struct GetUsersRequest {
	/// User ID. Multiple user IDs can be specified. Limit: 100.
	#[builder(default)]
	pub id: Vec<types::UserId>,
	/// User login name. Multiple login names can be specified. Limit: 100.
	#[builder(default)]
	pub login: Vec<types::UserName>,
	}

The id and login should really be &[&types::User{Id,Name}Ref].

[Emilgardis]

This is a duplicate of #114

This is definitely something I want solved, the hard part is how to do it and allow owning the data. (Cow comes to mind, which we've managed to implement fairly well in twitchchat, but not to a level I feel works well.)

[Nerixyz]

Sorry, I didn't see the issue.