Simplify repository setup

[kelson42]

The setup ask for the BorgBase token, but considering that in 99% we only need one, this could be advantageously saved in Bitwarden (master) account. The setup would then, just need the Bitwarden credentials which is simplier.

I propose that we agree on the name of the BorgBase item, like for example "BACKUP_BORGBASE_TOKEN". If the item is there then use it, otherwise ask the setuper to give it (interactivly).