Added option to force 4:3 aspect ratio

[vmzhivetyev]

Problem

Setup:

1. SkyZone sky04x v2 (not PRO) with 4:3 screen
2. Walksnail VRX
3. Walksnail Micro V2 Cam with 4:3 sensor

Situation:

• Sky04x goggles have 4:3 display but they get hdmi input in 16:9 format and scale it to fill the screen.
• In this case you have to use 4:3-FULL display mode in Walksnail VRX settings which also scales image coming from camera to occupy full screen. Otherwise the image would appear stretched in the goggles.
• Now you have 16:9 DVR recording done by the VRX but the camera image is stretched in width.
• To fix it you have to rescale the video bringing the aspect ratio back to 4:3.

Solution

Added a new checkbox which enables rescaling the final video (after overlaying the OSD) to 4:3 aspect ratio thus effectively shrinking it horizontally. The added ffmpeg option -aspect doesn't really change final resolution rather just specify pixel aspect ratio in the mp4 container.

[vmzhivetyev]

It seems the linter is not happy about the code in master:

error: field `commit` is never read
Error:    --> ui\src\util.rs:235:37
    |
235 |         Release { version: Version, commit: String },
    |         -------                     ^^^^^^
    |         |
    |         field in this variant
    |
    = note: `-D dead-code` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(dead_code)]`

error: could not compile `walksnail-osd-tool` (bin "walksnail-osd-tool") due to 1 previous error
Error: The process 'C:\Users\runneradmin\.cargo\bin\cargo.exe' failed with exit code 101