First draft of the PG 15 release notes

I have completed the first draft of the PG 15 release notes and you can
see the results here:

        https://momjian.us/pgsql_docs/release-15.html

The feature count is similar to recent major releases:

        release-10 195
        release-11 185
        release-12 198
        release-13 183
        release-14 229
-->     release-15 186

I assume there will be major adjustments in the next few weeks based on
feedback.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Indecision is a decision.  Inaction is an action.  Mark Batterson