Updated chief_deploy.py and update_site.py to do the same migration dance as the Puppet manifest.

- The update to chief_deploy.py needs to be changed to have the commit id of the commit that is going to be deployed. So probably not the merge commit, but the last commit shown in the pull request.
- The update to update_site.py needs to be removed right after merging the pull request.
Make sure the migration can be executed by depending on the latest available migration in waffle.
Make sure we install always the latest 1.4.x version in Vagrant.
Move events app into own app under the new kuma namespace.
Moved user profile model from devmo into users app.

- This also gets rid of lots of unused/unwanted code in the users app, e.g. email change model.
- Moved over tests and fixtures.
- Combines URL patterns of users and profile views.
Fixed templates after app move.

- deletes lots of unused template files
- removes links to removed views, e.g. old register view
- adds a simplified way to refer to user profile URLs `{{ <user>.get_absolute_url() }}`
Added initial events migration. This needs to be faked.
Removed all the devmo migrations and add users app migrations.
Minor cosmetic changes.
Removed unneeded rendering of the send_email_reminder form as it doesn't make sense anymore.
Use correct form to show errors for.
Add comment about a broken markup rendering.
Removed last trace of devmo from users URL patterns.
Move SubscriptionForm to landing app where it's used.
Fixed import.
Added kuma.events to list of apps to test.
Moved users app into kuma namespace.
Updated test instructions in MOTD and travis config.
Fix Bug #949510 - Add save buttons to bottom of page

Added copies of save/edit/discard etc. buttons to bottom of the page between review and attachments.

Made the buttons position:static so they wrap on mobile devices. Tweaked positioning of attachments add button to look good next to page buttons.