These vars are only used in the ad_hoc_reporting role, but their
prefix indicates that they're part of their services' roles.
This corrects the prefix.

The default is to enforce token checking (in edx-notes-api's common.py)
and we should be doing the same thing in deployed configuration.

Make this into a variable in case other systems (sandboxes?) want to
disable it in the future.

I suspect the third change is wrong - as is, it creates a route table,
but I cannot connect to the RDS.  However, there is no local gateway in
10.253.0.0 in loadtest, so the default isn't quite right either.

We should possible make SUBNET_[12]_CIDR easier to override, since I
ended up changing them anyway to use something other than .50.

This allows us to route LMS requests over an internal ELB while public
JS direct requests to the API go over a separate ELB.

This lets you run ansible-playbook with --skip-tags gather_static_assets
so you can redeploy edx-platform on your sandbox to test configuration
changes without waiting for paver.

COMMON_ENABLE_NEWRELIC turns on server monitoring and is on for all
sandboxes.  App monitoring should not be enabled for all sandboxes and
since edxapp workers is on all sandboxes, surprise newrelic!

This allows us to override the read preferences per module store in the lms.

They are not ready to go out yet so revert them until the corresponding edx-platform changes are in.

This way you can change read preference for one of the module stores
without effecting the other.

Also fix whitespace.

We need to have different read preferences in the CMS and LMS for modulestore configs so that the lms can read from the nearest node.

* Expose mobile store URLs setting to edxapp role.
* Remove deprecated social media URLs.