CDK-164: Add option for commands to register health checks (not just metrics) with the MorphlineContext
CDK-165: Add cdk-morphlines-metrics-servlets maven module with new `startReportingMetricsToHTTP` command that exposes liveness status, health check status, metrics state and thread dumps via a set of HTTP URIs served by Jetty, using the AdminServlet
bit more doc
bit more doc
sync instructions related to doc generation
only run deadlock detection if showJvmMetrics is configured to be true
CDK-166: Add registerJVMMetrics command that registers metrics related to the Java Virtual Machine
docs: add vertical spacing on jumping here via a link
Adding Hive storage URIs.

New hive storage URIs:
* hive => a managed hive repository
* hive:/tmp/repo-path => an external hive repo with the given path
* hive:/tmp/repo-path?hdfs-host=<h>&hdfs-port=<p> => above + HDFS info

The Hive metastore connection *must* be set up in the environment
because there is no way to pass the options via URI and the URI system
does not pass Configuration instances. This is because we want to have
Hive URIs working but don't know what they should look like yet. The
authority section of the hive:<path> URIs is reserved for this
connection information.

To make the scheme-less URI work, this adds minor changes to the
URIPattern class and tests to allow and check null schemes.

Hive URI registration works exactly like FS registration, with a
impl.Loader class that contains all of the needed OptionBuilders. The
Loader is listed in the cdk-data-hcatalog jar's services.
Updating FS URIs to fix minor problems.

When the URI path is relative and empty or null, it should be resolved
to the current directory, not the FS root.

Because URIs are matched in order of registration, the opaque URIs
should be added last so they don't accidentally consume valid
hierarchical URIs.

Also, this fixes the use of FileSystemDatasetRepository.Builder, which
should not use fileSystem. It now uses qualified paths instead.
Revert "Updating FS URIs to fix minor problems." since it caused
the tests to fail.

This reverts commit defb8bd64ed77c7841fde5ea8c5904074c26d9f6.
CDK-147. Deprecate constructors.
Fixing: Updating FS URIs to fix minor problems.

This commit fixes and restores defb8bd64ed77c7841fde5ea8c5904074c26d9f6.
URIPattern had a bug, where hierarchical URIs would try to match opaque
URIs. There was a check when the pattern was opaque, but when the
pattern was not and the potential match was, a NPE would get thrown when
trying to split the path (because opaque URIs have a null path).

Original commit message:

When the URI path is relative and empty or null, it should be resolved
to the current directory, not the FS root.

Because URIs are matched in order of registration, the opaque URIs
should be added last so they don't accidentally consume valid
hierarchical URIs.

Also, this fixes the use of FileSystemDatasetRepository.Builder, which
should not use fileSystem. It now uses qualified paths instead.