FEAT: manage multiple auth tokens

[Masber]

Currently manta only manage a single token for all sites, this is a problem because the auth token gets rewritten every time the user changes site. This means if a user is working on more than one site at the same time, manta will have to ask user for authentication.

This ticket is to make manta manage a token per site like:

Auth token for site1 --> ~/.cache/manta/auth_site1
Auth token for site2 --> ~/.cache/manta/auth_site2

Note: we need to adapt this to env variables
Note: make sure PSI understands this

[Masber]

fixed in v1.28.9