B-60565 - Enable JMX Metrics for Tomcat Connection Pools

NOTE:  this pull request requires on a corresponding one from puppet-atomhopper. Don't accept this until the other one has been accepted.

- Using Metrics 3.0 as its better documented than previous versions.  We might want to
  upgrade other components using earlier versions to 3.0.
- Added TomcatJdbcPoolGraphiteReporter which takes a map of DataSource beans and does the following:
  - Registers the associated MBeans with the JVM
  - Registers the associated MBeans with Metrics
  - Enables Metrics GraphiteReporter
- TomcatJdbcPoolGraphiteReporter is configured through application-context.xml