Add /help or /contacts command

[alecello]

To show reference figures for each area in the team, so new people know who to write to when in need

[lvps]

@alecello Do it by intersecting LDAP groups: Admin + one of the other groups (elettronica, programmazione, riparatori, ...) from a list, and also people in soviet but none of those groups

The other groups currently don't exist on LDAP, but we'll make them exist