Pull leeway out into var

Add a version override here so it's easy to update.

Analytics-Api will generally need to be built from a tag so that Insights
tests can run with that version.  Adding this line here to make it easier
to update when that process occurs.

Change migrate --list to showmigrations in pre_supervisor_checks

Django removed `migrate --list` in version 1.10 and added showmigrations in 1.8.
I left LMS, CMS, and xqueue alone because they have their own special way of
checking migrations.

become true for managing users and groups

Add xenial timing.

Without this, 2 builds happen, PR and push.  While this is technically correct,
it doesn't work well with our current test logic that attepmts to test only things
that have changed.  The push branch runs all the tests which is not what we want.
We may want to enable this again in the future when we have jenkins running all the
docker builds in parallel.

Feanil/ansible2x mongo

Update shiningpanda.

Use a .bashrc.d directory for more flexible configuration

We don't need git_2_0_1 any more, since we are on Ansible 2 now

set insights db host back to localhost

Can't be certs_user to set these permissions correctly.

We will need to assume the role for the correct account before running this role.

Explicitly set permissions for certs config.

Over tagged task and overrides.

Update bootstrap to be able to run a subset and run a subset when launching an instance.

XQWatcher user doesn't have permissions to update supervisor or restart it.

Supervisor needs permissions for two different users.

To check for migrations it needs to be able to read the lms.env.json and
lms.auth.json files for edxapp, and to be able to link services it needs
to be supervisor.

Set virtualbox network to virtio for speed