Consider consolidating base redis install and config into common

[JedMeister]

I have not yet had a close look at this, so perhaps it might not make as much sense as it seems from a casual perspective. But I think that it might be a good idea for there to be a common makefile &/or plan for redis (in common)?!

I note that there are a number of appliances that now ship with redis:

• canvas
• faveo-helpdesk
• mayan-edms
• nextcloud
• owncloud
• redis
• ushahidi

And perhaps foodsoft soon too?! (see #1565)

[qq7]

@JedMeister

I'm not so sure about this. Since we're installing Redis from Debian repos, it seems like doing this would only make difference in what one would be putting in plan: #include <turnkey/redis> or redis-server.