[BZ 1069547] Support shutdown of domain controller in ServerControl

This fixes the patching domain controllers which failed if restart
was demanded during the deployment.

Also optimized the reading of host.xml (to find the host of the domain
controller in the domain) to use SAX parser instead of DOM. This is
much lighter on resources and should also be much quicker because we
only need to read first couple of lines of the file.
[1001383] getResourceConfiguration does not return the current resource configuration
Improve some ConfigurationManagerRemote javadoc, making it more clear that
getLatestResourceConfigurationUpdate() satisifies the API request in the BZ (I think).
BZ 1124619 - provide more responsiveness when you want to ask an agent to update itself from the GUI. There is now a "update agent" operation, rather than requiring the user to use "update --update".
[1001383] getResourceConfiguration does not return the current resource configuration
Further improve the confusing/incomplete javadoc surrounding the get/find
configuration remote API methods.
BZ 1088032 - show a warning message if readlink doesn't exist.
[BZ 1070299] Added auto-start description from the EAP 6 documentation. The functionality for auto-strart field was already correct, just adding field description to avoid confusion.
Bug 1079303 - Excessive database size when using bundles causing UI to fail

This is a combination of 4 commits.
The first commit's message is:

Do not load histories when showing the deployments view.
Fetch histories aync when unfolding a resource deployment.

This is the 2nd commit message:

Database changes

Added index on resource deployment id in audit table
->Fast fetch histories aync when unfolding a resource deployment in the UI

Dropped foreign key on resource deployment id in audit table
->This is to prepare the async deletion of orphan audit messages when deleting a bundle deployment (or a bundle version, or even the bundle itself)

This is the 3rd commit message:

Added GUI messages so that the user gets correctly informed of what is going on

This is the 4th commit message:

1. No longer cascade remove audit message when deleting resource deployments
2. Purge orphaned audit messages in DataPurgeJob
3. No direct purge of audit messages during async resource deletion job

Also, I increased the default batch size property, as my testing showed 1.5x higher performance (tested on 1 million and on 5 million rows).
A community user with a large RHQ deployment reported better results with higher batch size as well.