Add --no-cleanup option

It might be useful not to cleanup on exit, for example to leave the
screen turned off, or keep the server binary on the device (via the
server option "cleanup=false").

Fixes #1764 <https://github.com/Genymobile/scrcpy/issues/1764>
PR #3020 <https://github.com/Genymobile/scrcpy/pull/3020>