This utilizes the new metrics support in ironic-lib to allow the agent to
report timing metrics for agent API methods as configured in ironic-lib.
Additionally, this adds developer docs on how to use metrics in IPA,
including some caveats specific to ironic-lib.metrics use in IPA.
Co-Authored-By: Jay Faulkner <jay@jvf.cc>
Co-Authored-By: Alex Weeks <alex.weeks@gmail.com>
Change-Id: Ic08d4ff78b6fb614b474b956a32eac352a14262a
Partial-bug: #1526219
fd874652e3