Added "Import" button in Global Sources Dialog.

The "Import" button opens a "Open" dialog where a user can open a scene collection file then it lists all Global Sources from the selected scene collection in a dialog.

You can Import multiple global sources by holding shift or Ctrl and clicking on the Global sources you want to import.

With this change scene collections have their own Global Sources but users can import Global Sources from other scene collections.

If you make any changes to a Global sources properties and want the change in another scene collection you will need to remove the global source in the other scene collection and then import it again.

You can't import Global Sources if there is already a Global Source with the same name.

Hopefully this makes it simple and fast for users to import their commonly used Global sources like for
example followers alerts.
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
Update version to 0.63 test 3
Merge pull request #362 from Glought/SceneCollectionGlobalSourcesImport

Added "Import" button in Global Sources Dialog.
Restore missing Replay Buffer tooltip
Add warning when starting Replay Buffer without setting hotkeys
Improve Replay Buffer length error handling
Fix QSV Settings not being enabled with QSV selected