Support using advanced types with aura:method

[aheber]

There are advances uses for having the component method expose fully flexible TS types. We should support a syntax that allows us to declare these in the file so the d.ts files can be built with these to expose better interfaces.

[aheber]

Should probably support this for any and all Component generated types (attributes, methods, events...). More or less a typing override syntax, probably something added to the description attribute like a JSDoc formatted string.