(PDB-863) Remove com. from jmx and mq endpoints

This commit removes the com. from the jmx and mq endpoints so that these
endpoints use the new puppetlabs.puppetdb namespace. In order to change
all the outstanding references to the old namespace, this commit also
updates the dashboard index.html to reference the v4 metrics api.
Merge pull request #1169 from ajroetker/pdb-863_remove_com_from_jmx_mq_endpoints

(PDB-863) Remove com. from jmx and mq endpoints