Use exponential decrease instead of logs for confidence calculation. Reduce related configstring update frequency.
Remove stagedown thresholds. On stageup, teams will get a confidence bonus instead.

The size of the bonus is determined by g_minimumStageTime (in s).
A value of 60 means that you will keep the higher stage for atleast a minute.
Merge branch 'gameplay/viech' into bots+viech