(PDB-843) Squash puppetlabs.http and puppetdb.http

These two files are a source of confusion as we develop, and the pending
namespace change requires us to do something with them. This patch simply
squashes the functions into one library for now, and removes any reference
in other libraries. The pl-http short name is also dropped now.

Signed-off-by: Ken Barber <ken@bob.sh>
(PDB-843) Namespace changes for source and test code

Our engineering org has decided to use puppetlabs.<library_name> as a standard
across our Clojure projects, this patch lines us up with that standard.

This also moves the libraries in com.puppetlabs.* into puppetlabs.puppetdb also,
to avoid collisions with any other project. These files were designed to be
pulled out of PuppetDB one day, but for now we've moved them all into the same
namespace.

We also have re-aligned our tests to be more standard, adopting the namespace-test
convention. This aids with editors also, as now we can switch easily between src
and test.

All the various places that care about this change have been changed, including
SysV scripts, systemd definitions and the command line utilies that are responsible
for launching PuppetDB, since we now have puppetlabs.puppetdb.core as the main
entry point. boostrap.cfg, and logback.xml have been changed also.

Since we were changing a lot of the (ns ..) blocks across all files we took the
opportunity to clean them up. :use is now now longer used (excuse the pun).
Comments at the top of libraries are now in the ns doctstring also.

The test-resources directory has also been aligned with the new namespaces and
tests are now pointing at the new layout.

For backwards compatibility, we've kept the old namespace pinned for JMX & ActiveMQ
queues, since these are still required for our stable API commitments. In the future
we'll have to fix this.

The concurrent.clj code has been removed, I found it wasn't used so removed it.

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #1078 from kbarber/ticket/master/pdb-843-rationalize-clojure-namespaces

(PDB-843) rationalize clojure namespaces
(PDB-653) metrics update on PDB start

Previously the DLO metrics only updated on a failed command submission, which
meant restarting PDB would blank the metrics until the next failure. This patch
initializes DLO metrics on PDB startup if the DLO directory, which is created
on first failure, already exists.