Re-add saving of favorite servers

[rvstwi]

Right now favorite server variable is ignored - I think OMPW just sets it to true for every server IIRC. We should re-allow players to save favorite servers, and allow sorting by favorite.

Similar to #30

[ijemafe]

I'll take a look at this as part of the MP widget overhaul with sorting and filtering.

[ijemafe]

Relevant code:

• The stGameServer type has a bFavorite field: https://github.com/ijemafe/raven-shield-1.56/blob/master/R6GameService/Classes/R6ServerList.uc#L125