Update and improve email templates
This PR contains the following changes:
* Rename all email templates in the form TYPE_#_DESCRIPTION.txt for
better sorting.
* Streamlined committer invite process:
* Per discussion on dev@community with Craig Russell, new recommendation
is to point the candidate immediately at the iCLA so they can get on
with it, rather than unnecessarily delaying the process.
* Info in the initial response after committer acceptance was moved into
the next or prior email, as appropriate
* Addition of new PMC member vote / result templates
* Minor updates to the release process templates, consistent with the
2.2.0 and 2.3.0 releases
* Minor updates to other templates - outdated URLs, etc.
* Removal of templates we don't use anymore:
* release discussion (merged with release notice)
* release discussion python script (1.x)
* archive discussion (follow ASF policy, archive more aggressively)
* merge discussion (replaced by GitHub PRs)
* release notes discussion (merged with release notice)
* board report request for help (no longer necessary)
36 files changed
