Custom Local Capture Save Location Option

[GrantComm]

Adds custom local save directory for pm4 captures in addition to gfxr captures.

Manual Testing:
Linux:
Open capture window, perform gfxr capture, perform pm4 capture. Ensure if local save dir is not entered, capture file is saved to "dive_capture_file"

[RenfengLiu]

Thanks for putting this together.

[GrantComm]

Please start reviewing at 35629a3. Capture workers are from #619

[hysw]

Please start reviewing at 35629a3. Capture workers are from #619

Might be worth while editing the PR description to include diffbase.