Login with several providers + Logout

[FdezAriasSara]

Small issue to address:

• [x] Make the dropdown menu in login view work

• [x] Add functionality to logout button

[FdezAriasSara]

@Batuhanbyr
I changed the dialogue from this:

to this:

So the user can close the dialog without logging out.

Also i made the typography a little bit bigger and moved part of the styling to a css file using Grid Layout