feat: support for other file interfaces that called "extends"

[rdlabo]

Right now, it does not support types called from other files.
Like: https://github.com/capacitor-community/admob/blob/feat/v3/src/definitions.ts

I believe this will help in the refactoring of many of the plugins once it is supported.

[jcesarmobile]

reopening since I've reverted #24 on #39