and prometheus collector backend support.

* Fix various remaining typos.
* Fix trailing character on reno.
* Enable Elasticsearch when selected as cloudkitty backend.
* Add a check for ES index creation when ES required.
* Add a release note
* Fix release note line length issue.

Change-Id: I18f3d8f2e10a2996b2ebf92733a1770bef548bda
Closes-bug: #1895945