HostTracker hosts DB key scheme implementation

Requirements :-

i) IP only scheme for hosttracker hosts db key is by default supported.
ii) IP + MAC scheme for hosttracker hosts db key addition.
iii) Only one scheme at a time will be active. The configuration is
controller by the setting hosttracker.keyscheme in config.ini. By default
it has a value of zero which indicates IP only scheme.
The value 1 can be set for choosing IP+MAC scheme.

Changes done :-

i) Marker interface named IHostId is used for the implementation.
ii) IPHostId and IPMacHostId are the classes which implement the marker
interface.
iii) All the hostttracker apis have been aligned to the new key using the
marker interface IHostId as the key.
iv) Version of the hosttracker and it's dependent bundles like
arphandler,loadbalancer,static routing etc.. have been bumped up.
v) HostIdFactory has been provided to create the keys based on the scheme
the user is using.

Tests done :-

i) pingall has worked.
ii) NB APIs of hosttracker.

Made distribution changes which were needed and other pom changes as well.
Integration test for hosttracker has been fixed with the right version.
Other module integration test failures and review comments have been taken
care off.
Host DB Key classes have been serialized.

Change-Id: I328a1b6d3702d5268832f0e3ea6ee47122f20205
Signed-off-by: Deepak <dudapudi@in.ibm.com>