OPS-1593 As an operator, I want sudo_user converted to become user in roles and plays, for compatibility with Ansible 2.x

The headers were pointing to the old github wiki. Since we've officially
moved to Confluence, these links should be updated.

Otherwise the command fails if the password includes special shell
characters such as '&' or '<'

refactoring common inclusion based on comments

removing motd template from common

Removing sshd template

relocating temlates

relocating templates

Relocating dhclient templates

explicit play depends

Update responsibilities

indent

further dependency updates

additional updates

Common dependency for server utils

Supervisor is required for role integrity

Typos

further template ownership changes

In particular LocMemCache doesn't have this option.

For more details, see:

http://stackoverflow.com/questions/23358787/memcache-get-returns-wrong-object-celery-django

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.