Forcing a plugin to create and register simauth at once is sometimes
inconvenient. This patch separates the creation and registration
into two API's, and also adds several others to add the required simauth
data incrementally (identity, driver data, sim/aka support). This also
allows for the driver to unregister the auth provider without freeing
up the simauth object itself e.g. if the driver temporarily becomes
unavailable, but will come back sometime in the future.
The simauth watch API's were also renamed. Watchers will now get a
callback when the provider has been unregistered, so they have been
renamed to sim_auth_unregistered_watch_[add|remove].
This is the core module that takes care of registering
authentication drivers. EAP-SIM/AKA will be able to acquire
a driver that supports the required algorithms. The driver
implementation (hardcoded/ofono etc.) is isolated into
separate plugin modules.
