Don't expose the UAConfig in the API & load it via file-embed.

A UAConfig really is an implementation detail which users should not have to worry about. So this patch simplifies the API by loading the UAConfig internally.

Also, instead of loading the file dynamically, it's embedded in the library which makes it easier to deploy executables which use this library.

These simplifications also enable to get rid of the Web.UAParser.Core module which again simplifies the API.

@ozataman what do you think of these changes? BTW thanks for this nice package, we're about to use it at Better.