Intercept okhttp3 responses to determine if Moodle token is still valid or not

[abhijeetviswa]

Interceptors could be used for this. This would be easier than checking if token is valid or not at every point in the codebase where a request is sent.

[fynngodau]

I think this is a great idea. For the moodleDirect fork, I implemented it like this: https://codeberg.org/fynngodau/moodleDirect/commit/66f9309b834b3c61dddd7c8fb0a8a2bfb0679080

This way I can detect whenever a moodle Exception needs to be thrown.