XD-1490 support absolute path in CacheServer
XD-1580: Undeploy modules when ZK disconnects

In method registerWithZooKeeper, the module deployments cache is
started before saving the container attributes. This way if there
is an exception thrown while saving the attributes, the deployments
cache is not affected.

At some point we may want to consider trapping exceptions from
this method, or perhaps even shutting down the ZK connection if
an exception occurs. I was seeing a NodeExists exception for
the ephemeral node created by this method, but that exception
seems to have gone away with the other changes in this commit.

In method onDisconnect the modules are now undeployed when the
connection to ZK is lost. This is desirable because the admin
leader will try to redeploy those modules on another container.

In StreamModuleWatcher and JobModuleWatcher, instead of blindly
setting the watch on every non-delete event, the watch is only
set if the connection to ZK is established. This change seems
to prevent the exception described above in registerWithZooKeeper
although I don't understand how they are related.
XD-1501 Empty defaultData for znode paths

- By default CuratorFrameworkFactory.Builder sets the defaultData to local host address.
This causes the local host address being updated inside the znode path.
- Set Builder's defaultData to empty byte array so that it is empty by default
when PathAndBytesable.forPath(String) is used
removed comment from message-bus.xml
XD-1592 use classpath* url in message-bus.xml
removed comment from codec.xml
Fix RemoteFileToHadoopTests

- Set application context explicitly for the LocalMessageBus inside the test
Use Msgbus binding to start

- The messagebus implementations, upon registration of consumer and producer from/to messagebus
the corresponding endpoints start.
  - Instead of directly calling the start() on adapter/consumer we can call the corresponding Binding's start()
     - This is in-line with the way the corresponding endpoints are stopped (using Binding's stop()) during
undeploy/destroy
XD-1595 Remove aliasHint in MessageBus

- Remove the use of `aliasHint` flag in MessageBus bindProduce/Consumer
- Fixed `LocalMessageBus` to use `QueueChannel` provider in case of named channels (p2p channel & job input channel)
- Fixed the tests
- Remove the methods isAliasedInput()/isAliasedOutput() in Stream/Job plugins
as they are no longer needed and the Source/Sink channel names are already set
in the DeploymentMetadata if the input/output channel name is aliased