Add camera mirroring

Add --video-source=camera, and related options:
 - --camera-id=<id>: select the camera by its id (see --list-cameras);
 - --camera-size=<width>x<height>: select the capture size.

Fixed #241 <https://github.com/Genymobile/scrcpy/issues/241>
PR #4213 <https://github.com/Genymobile/scrcpy/pull/4213>

Co-authored-by: Romain Vimont <rom@rom1v.com>
Signed-off-by: Romain Vimont <rom@rom1v.com>

app/data/bash-completion/scrcpy

@@ -10,6 +10,8 @@ _scrcpy() {
         --audio-source=
         --audio-output-buffer=
         -b --video-bit-rate=
+        --camera-id=
+        --camera-size=
         --crop=
         -d --select-usb
         --disable-screensaver
@@ -74,6 +76,7 @@ _scrcpy() {
         --video-codec=
         --video-codec-options=
         --video-encoder=
+        --video-source=
         -w --stay-awake
         --window-borderless
         --window-title=
@@ -93,6 +96,10 @@ _scrcpy() {
             COMPREPLY=($(compgen -W 'opus aac raw' -- "$cur"))
             return
             ;;
+        --video-source)
+            COMPREPLY=($(compgen -W 'display camera' -- "$cur"))
+            return
+            ;;
         --audio-source)
             COMPREPLY=($(compgen -W 'output mic' -- "$cur"))
             return
@@ -141,6 +148,8 @@ _scrcpy() {
         |--audio-codec-options \
         |--audio-encoder \
         |--audio-output-buffer \
+        |--camera-id \
+        |--camera-size \
         |--crop \
         |--display-id \
         |--display-buffer \