Decouple the HBase internals such that someone can implement
their own SASL-based authentication mechanism and plug it into
HBase RegionServers/Masters.
Comes with a design doc in dev-support/design-docs and an example in
hbase-examples known as "Shade" which uses a flat-password file
for authenticating users.
Closes#884
Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org>
Signed-off-by: Andrew Purtell <apurtell@apache.org>
Signed-off-by: Reid Chan <reidchan@apache.org>
Josh Elser