Add the ability to remove stations/connections

[Capkirk123]

Although this is a little bit antithetical to the inspiration behind Skopos, it would really be nice to actually permanently remove connections.

This is mostly useful for experimental stuff, like Syncom where the USNS Kingsport exists only for Syncom, or the early transpacific contracts where Point Mugu was replaced by proper AT&T terminals for intelsat.

Being able to actually cull ground stations from experimental/short term contracts so they don't clutter the map would be nice to have.