Load templates from GitHub

[The0mikkel]

Load templates from GitHub, and default to local templates, if local templates are present.
This makes it a lot easier to get started.

However, this introduces the problem of selecting the correct template versions from GitHub.
Allowing for local templates is a must for the tool.

[The0mikkel]

importlib.resources could help resolve versioning issues when retrieving from package.
Thanks @VaiTon