Display generic user in project member admin area

Change-Id: Ic14ad26ab74a2114ea98fa54d81f24dd199d0281
Refactoring to provide a consistent User

With the previous implementation, when you `fetch` a GenericUser you do not get
all the user data (eg: $generic_user->getEmail() returned empty Otring instead
of data from the db)

Now we inject the (PF)User coming from the db in the generic user.

Change-Id: Ica0719d3575044c9dfc5ff8f5191cc6f61017746
Allow project admin to change generic user settings

Add new interface in project admin to change the email and the password of the
generic account of the project.

This is a revolution!

Change-Id: Ia052cf15ebde49f098490c013f0953bc1e7d49b4
Merge commit 'refs/changes/72/572/4' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  Allow project admin to change generic user settings
  Refactoring to provide a consistent User
  Display generic user in project member admin area

Change-Id: I22768c83506def7775ec8e6f7f1937974a71fc90
This is Tuleap 6.2.99.4

Change-Id: I563e27da2b194ee80e51e8937f1c257b429e0c90