release creation script(s)

[cpoerschke]

Yesterday (2017-06-20) there was a ponymail mailing list thread re: release creation. This pull request explores having a script for (most or all of) the steps (on http://ponymail.incubator.apache.org/building.html).

Sample output of initial version:

prompt$ python3 dev-tools/scripts/buildAndPushRelease.py 0.10
Create a new branch off master called 0.10 (ideally, master is always releasable).
  git checkout -b 0.10 master
Tarball the 0.10 branch, sans the .git directory:
  git archive --format=tar.gz -o ~/ponymail-0.10.tar.gz HEAD
Create checksums of the archive (make sure your PGP key is in our KEYS file!):
  Make a checksum for the archive itself:
    sha256sum ~/ponymail-0.10.tar.gz > ~/ponymail-0.10.tar.gz.sha256
  Sign the archive:
    gpg --output ~/ponymail-0.10.tar.gz.asc --sign ~/ponymail-0.10.tar.gz
  OR
    gpg --output ~/ponymail-0.10.tar.gz.sha256.asc --sign ~/ponymail-0.10.tar.gz.sha256
Push the artefacts to https://dist.apache.org/repos/dist/dev/incubator/ponymail/ via subversion
  svn ???

[Humbedooh]

Seems to be some lucene/solr stuff in there - a copy-pasto perhaps?

[sebbASF]

Also it's really hard to see what is happening in the script. Would it be possible to create a shell script instead?