* Updates to the Community Code of Conduct
Fleshes out the Code of Conduct, with adaptations from the Contributor
Covenant and the Elastic.co Community Code of Conduct.
* Better format subsections
* Use strong emphasis instead of sections
* Set subsections correctly and add newline after strong emphasis
added info/link for ansible-lockdown to mailing list section, minor editing
(can't help myself it seems) to the paragraph about subscribing from a non-google account
The bit about git rebase vs git merge is repeated in the paragraph below. The bit about test/integration is repeated in the paragraph above.
(And the bit about aliasing git pull to git pull --rebase is unclear, since git's aliases cannot override builtin operations.)