Rename lp-translators team to launchpad-translators

Following the UDS discussion regarding the following blueprint https://blueprints.edge.launchpad.net/rosetta/+spec/launchpad-translators-group , we would like to have an open "Launchpad Translators" group for gathering all LP users interes in doing translations using LP.

We will use this team for hosting a mailinglist but also as a contact for translation related bugs or answers.

Many thanks!
Adi