Flag Return Cycle Improvements

[xezno]

This might fit here, the flag needs a more clear return cycle, part of it is particle work but some of it might also be UI work for conveying how far along the flag is to respawning and this being a little bar would also show it returning faster when you're in the flag's return zone.

• Add return zone so teams can actively return and defend/hold the flag on the floor
• Show some sort of UI meter/bar instead of debug timer visual
• Clear pickup sound
• Clear capture sound
• Clear drop sound
• Clear taken sound