Add DiracX tokens for pilot proxies

[Robin-Van-de-Merghel]

Currently, dirac-proxy-init embed a token in a proxy, but the site director does not for pilots.

It could be useful to help the transition toward DiracX to embed a token in it: we could send logs as of now (such as #8268), construct logic in DiracX and use it right now for pilots.

These pilots would have a user token and not a pilot token, but still the logic would be implemented and tested in DiracX.

[fstagni]

@Robin-Van-de-Merghel good point. Would you have time to give it a try?

[Robin-Van-de-Merghel]

I finish with secrets with DIRAC (Integration test) and maybe I'll try