While COMMON_OBJECT_STORE_LOG_SYNC and related variables are still
supported, this patch offers a finer grained control over tracking log
syncing.

Sometimes you want to host edX on openstack (and therefore need to run
the openstack role), but you still want to sync tracking logs to S3, so
it does not make sense to tie the choice of log sync store to the
presence of either aws or openstack role in the playbook.

The vhost role used to create directories required by the aws and
openstack roles based on the value of the VHOST_NAME variable, but that
turned out to be problematic (see https://github.com/edx/configuration/pull/3519).

Remove the VHOST_NAME variable and make each aws and openstack role
responsible for creating its own directories.

This adds two new variables to common_vars:

- COMMON_ENABLE_AWS_INTEGRATION
- COMMON_ENABLE_OPENSTACK_INTEGRATION

They are both set to False by default. When set to True, the
corresponding role (aws/openstack) will be automatically included in
edx_sandbox.yml and edx-stateless.yml playbooks.

We already do this in the common role but not in bootstrap or abbey roles.

(cherry picked from commit b78c0487)

See https://github.com/ansible/ansible/issues/21316

This prevented successful installation of open-release/ficus.1rc

(cherry picked from commit a79fe1b7)

Apply the change to install MySQL 5.6 from an edX PPA

(cherry picked from commit 6218350b)

(cherry picked from commit b8ed4f49)

(cherry picked from commit 6e4a47de)

Cherry pick from c6514cca

Use my-passwords.yml in sandbox.sh

(cherry picked from commit f3970b73af316502722e6153f11af52f7b61112d)
(cherry picked from commit 81cc046ff09e69642eeb7cb82aa1f7b08b28c649)

(cherry picked from commit b2beddb4d35c12537d17454e543363201c578cd8)

Cherry-picked from 5 commits, from PR's #3654 and #3670:

(cherry picked from commit 3df8af7f)

(cherry picked from commit 8cad356a)

(cherry picked from commit 2ef0aa42)

(cherry picked from commit 59b50c82)

(cherry picked from commit 00be986f)

(cherry picked from commit a3975c4e)

This should help decrease build times.

ECOM-6600

Cherry pick from 64facf1b

Cherry picked from e4cacb16

Fix #21

Cherry picked from 31b6ee56028550b9aa9fac840f3f2040fadaeaf2

Pin nodeenv's node version to 6.9.4 LTS for Platform, Ecommerce, Insights and Credentials

Fullstack is now a native install, in Vagrant

(cherry picked from commit 9d3475d4)

Installs python 2.7 using raw ansible commands.

`python` role is prepended to edx_sandbox.yml and edx-stateless.yml in a
prefix playbook, so that gather_facts can be "no".