Release metrics-lib version 1.0.0
We should do metrics-lib releases and provide jar files for each release. We could start with version 1.0.0, because metrics-lib is already in use by a couple of projects and has turned out to be relatively stable. Blocking on a solution to #13132 (moved) to distribute jars, plus a few more decisions on ChangeLog format and a versioning scheme, some code for an Ant task, etc.