prefix vars to avoid namespace clashes

[nusenu]

Follow best practices and prefix your role variables.

mentioned in #75 and
https://galaxy.ansible.com/intro

I find "relayor_" a rather long prefix and would prefer "tor_" or "torr_" (short tor relay), because I guess it is unlikely that people will run multiple tor roles.

Note: This change will break existing setups since they will have to update their playbooks.

For this reason we will commit this once we start to require tor v0.2.8.x (see #71 )

[ypid]

Note that DebOps has a procedure in place to do variable renames (ref: Migration/upgrade notes) so this could be semi-automated and users only have to run a command.

About the name, I would not mind so much to keep the variable names to a minimum but that might come from my practice to copy/paste variables from the default file and then modifying them. Also, I would prefer a more descriptive role name which could then also be used for the variables, like nusenu.tor_relay and then using the name space tor_relay__ for the role (the __ comes from DebOps and was introduced to make working with role dependencies visible). Anyway.

If the only reason to not use relayor_ or relayor__ is the length then this might be debatable (we are talking 8-9 against 4-5 characters ("tor_" or "torr_") here) 😄

@nusenu BTW: I like how you handle the release management 😉