Map identities to proper objects

Change the binding type mapping from Class<? extends BaseIdetity>
to proper objects. While this imposes some runtime footprint in terms of
loaded classes (there is an anonymous implementation of each identity)
and objects (that implementation is an eager singleton), it removes a
metric ton of irregularities. This this change, all mapped objects
objects can be checked via 'instanceof' and most of them have
implementedInterface() for exact contract matches.

JIRA: MDSAL-733
Change-Id: Iab7dfb7656db87850613f567dfe40ef31494f6c4
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>