contactmodel: Add banned contacts logic

The old lrc bannedaccountmodel suffers from many issues, both in its
design and functions. In order to be able to later remove this code,
migrate the banned contacts logic to the contactmodel.

contactmodel:

 - add a bannedContacts list with its mutex to store uris of banned
   contacts (not necessary but important for perfs).
 - modify addContact() to call directly addContact() (daemon side)
   when called with a banned contact. This will replace the old
   remove() method from the bannedAccountModel.
 - add a getBannedContacts method.
 - modify slotContactAdded to maintain the bannedContacts list and
   the old lrc. Also, when called with a banned contact, only refresh
   the filters, do not emit contactAdded signal.
 - modify slotContactRemoved to maintain the bannedContacts list.
 - modify addToContacts to maintain the bannedContacts list and
   update banned flags from the contactInfo.

bannedcontactmodel (old lrc):

 - do not update daemon when remove is called since it collides with
   the contactmodel.

   _Using the bannedcontactmodel from old LRC for maintaining banned
   contacts is now DEPRECATED and support for this functionnality is
   planned to be dropped in a near future. Please migrate to the new
   contactmodel banned contacts features._

   The recommended way to unban a contact is to call addContact. This
   is symmetric to the way we ban contacts (calling removeContact).

configuration manager mock:

 - add a synchronization mechanism to the configuration manager mock
   in order to avoid race conditions during concurrent execution of
   several removeContact / addContact functions
 - modify addContact to correctly behave if called with a banned
   contact: Instead of re-adding the contact, banned and removed
   flags should be cleared.
 - modify removeContact to use find_if instead of a for loop and
   erase contacts from the contacts list instead of simply removing
   them.

tests:

 - add a unbanContact helper.
 - fix testPlaceCallWithBannedContact to check callId instead of
   conversation size which is pointless because invariant.
 - modify all banned contacts related tests to unban and re-check.
 - add a testBanUnbanContact test.

Change-Id: I42b90559ca4baa12f0596bb927009ce6ba8b4ea3
Reviewed-by: Sebastien Blin <sebastien.blin@savoirfairelinux.com>