Snapshot release to current stable 22.03.3 release

[account4538]

bcm53xx uses the same image for factory.bin and sysupgrade:

Luxul XBR-4500: Upgrading OpenWrt when there is no sysupgrade image

Targets I maintain / develop (bcm47xx, bcm53xx and bcm4908) don't require OpenWrt-custom sysupgrade images. It's a single image that can be used for both: Initial installation (from vendor custom firmware) OpenWrt's sysupgrade. So worry not - just use the available firmware image. OpenWrt's sysupgrade on those targets can be used for both: Reverting to vendor firmware Upgrading OpenWrt I believe / hope it's actually a simpler & easier solution. Get image and flash it. Don't worry about ve…