Document how users can add IRC support back themselves
Parent issue: #8573
Once we drop Pidgin, likely its replacement won't support IRC.
On #15816 (closed) we reached the conclusion that it was OK to drop IRC support by default, but we should smooth a bit the transition, in order to lower the noise this will create, and ease the pain on Help Desk.
- Keep the Pidgin configuration in our image
- Drop the Pidgin persistence feature: otherwise it's visible to everybody and we need to keep the corresponding doc
- Document a way to add and configure Pidgin in a persistent manner
- Install via Additional Software
~/.purplepersistent, e.g. by adding a line to
persistence.confor via dotfiles
For the discussion that lead there initially, see #15816 (closed).