Raise an exception with the error message only when there is one
Full path imports and allow to use single letter code to pass (p) or deny (d) an action
Retrieve the username and use it when creating the FAS client

The username allowing to load/save the session data from the filesystem
Rework the get_bug method to ask for login only if needed

Before calling bugzilla we do not know if the user can log in or not. We
could call .login() but that would require asking the user for his/her
username and password everytime.
So instead we query bugzilla once, and based on the output we determine
if we need to call .login() or not (as bugzilla stores a token on disk
credentials are not necessary for every calls).
Adjust __get_fas_user_by_email

We might have situations where the email address does not correspond to
an user in FAS, we should be able to handle such situation.
Inform the user if an email address does not correspond to a FAS user
Adjust the call via FASCLIENT

As the FAS client stores its cookie on disk, it is not necessary to ask
for the user's credentials every time, instead we can ask them only when
FAS says we need to.
Drop log as it's undefined and catch more AuthError from FAS
Get the shortcuts to approve (a), deny (d) and pass (p) to work