Add functionality to support basic auth requests

[hodovani]

Add an optional input form to support connection to a server with basic auth.

[ltalirz]

thanks - you let me know when you would like a review

[blokhin]

@eimrek we did this feature collaboratively with Matvii, and I think it was working on our side, please, give it a try?

[blokhin]

w.r.t. #31

[eimrek]

hi @blokhin! we're soon deprecating this repository, as we're currently working on making a new aiida-explorer here: https://github.com/aiidateam/aiida-explorer

It's very early in development stage, but should soon (by the end of summer) replace this current version.

Unfortunately we don't have time to work on this version any more.

But of course, if you want to keep using this and add extra functionality, feel free to maintain a fork.

[blokhin]

@eimrek OK, sure, I didn’t know about the new version. Anyway, no problem, will be happy to compare the old and the new one!