[Hawkular-dev] [metrics] remove support for tagging data points

Early on in the project, I added some support for tagging individual data points, primarily as a PoC. To the best of my knowledge, that functionality is not used. Tagging metrics on the other hand is used. I created https://issues.jboss.org/browse/HWKMETRICS-247 <https://issues.jboss.org/browse/HWKMETRICS-247> to address removing the relevant code and making the necessary schema changes. If this functionality is used or if there are objections, please add a comment on the ticket; otherwise, I would like to make these changes for the next metrics release. - John