Add guard to handle twitch extension api requests

[ghostzero]

• Add extension guard for extensions
• Bump php support, since it's not supported anymore(including security updates)

TODO:

• Complete docs

[ghostzero]

Seems to work now :D

[Katzen48]

Btw. I don't think the tests below PHP 8.0 are necessary. Every version < PHP 8.0 doesn't even get security updates anymore and even PHP 8.0 is out of active support.

[romanzipp]

To be honest I don't really understand which use case will be covered with adding an auth guard. Could you share an example?

[Katzen48]

When making an extension, you may need to call your backend. For authentication, Twitch provides a JWT signed by the Twitch backend (see docs).

A guard for this use case could reduce the work for implementing this in every project anew.