Add virtual display feature

Add a feature to create a new (separate) virtual display instead of
mirroring the device screen:

    scrcpy --new-display=1920x1080
    scrcpy --new-display=1920x1080/420  # force 420 dpi
    scrcpy --new-display       # use the default screen size and density
    scrcpy --new-display=/240  # use the default screen size and 240 dpi

Co-authored-by: Simon Chan <1330321+yume-chan@users.noreply.github.com>
Co-authored-by: anirudhb <anirudhb@users.noreply.github.com>

app/data/bash-completion/scrcpy

@@ -46,6 +46,8 @@ _scrcpy() {
         --mouse-bind=
         -n --no-control
         -N --no-playback
+        --new-display
+        --new-display=
         --no-audio
         --no-audio-playback
         --no-cleanup