HTTP auth workaround

It is a work in progress. For sure the CI won't pass since the 2 MR first need to be merged. I'm going to rebase when it's done.

These modifications should fix some issues related with using http and https (for example #267 (closed) and #275 (closed)).

At home, clone, push, ingoing and outgoing work via https for public and private repository.

It is important that the password is not asked for readonly operations (in particular clone and pull) on public repository.

I didn't know how to check that the repository is public. How would you do that?