Windows AD clien + Server setup documentation

The file AD_client.md and AD_server.md includes the start up guide
for setting up windows AD to work with 'swiftkerbauth' code.

Bug: N/A

Testing: N/A

Signed-off-by: Chetan Risbud <crisbud@redhat.com>
Merge branch 'master' of https://github.com/prashanthpai/swiftkerbauth

Signed-off-by: Chetan Risbud <crisbud@redhat.com>

Conflicts:
	doc/AD_client.md