Deprecate URL apis in favor of GlideUrl

[sjudd]

The URL class has a number of problems, we shouldn't be encouraging people to use it. Using strings or just GlideUrl directly is substantially more performant.

[TWiStErRob]

My two cents:
If someone already has a URL (e.g. received from a library) they shouldn't have to write more code to convert it to GlideUrl or String which will then convert it back to some object anyway.

@Deprecated with an explanation should be sufficient, but don't plan to remove it.

NB: I'm also lost in this world of String/URL/URI/Uri/File/Path/FileDescriptor/..., so many things to describe something very similar. I was just too lazy to look it up, probably others did the same.

[sjudd]

Ugh I closed the wrong issue from that commit.

Yeah I think @deprecated is sufficient. The goal here is to emphasize that it's a performance problem to obtain and use URLs directly because constructing a URL, URL#equals and URL#hashcode all perform network operations. The GlideUrl class largely mitigates this, but can't do anything about the constructor jank.

Ugh yes URL vs URI vs Uri in particular is frustrating, particularly because URL looks like exactly what you want if you're trying to do http/https, but in fact is usually not what you want unless you're actually trying to perform a network request.