Clarify the error related to aadarchi.github.token

[Riduidel]

Message is not clear enough to help user connect to GitHub.

Fill the page How to add aadarchi.github.token? in aadarchi wiki explaining the different steps required:

1. Create a github token (see https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token)
2. Add github token to settings.xml in a profile that is loaded (see https://maven.apache.org/settings.html and https://stackoverflow.com/a/37312347)
3. Restart build