Add StringList::Join utility
Refactor status bar output status handling
Separate Replay Buffer from normal file recording
Add date/time replacement for save path

Also OBS will now automatically create directories when needed
Add separate setting for Replay Buffer File Path
Add Record from Replay Buffer

This basically saves the current replay buffer and continues recording
to the saved file. The recording uses the standard file path.
Share memory between ReplayBuffer and RecordingHelper
Throttle RecordingHelper::AddPacket to keep buffer from filling RAM

For each incoming video packet two more video packets should be written
by the save thread to make sure that the buffer drains
Improve RecordingHelper::SaveThread shutdown behaviour

This gives unfinished recordings a bit more time to write the remaining
buffered packets before threads are (potentially) terminated