feat(color): additions to Lvgl for Lua scripts

[philmoz]

Create a Lua tool script with a header to match firmware pages.
Supports:

• top left icon acts as RTN button like firmware pages
• has title and subtitle lines
• top left icon can be a custom image, or EdgeTX icon
• 'back' action script called when RTN button pressed or top left button tapped.

Closes #1151, foundation for #4614 on colorlcd

Test script (updated to include multi page demo and QR code):
Lvgl Page Test Tool .lua.zip

[philmoz]

lua.pages.mp4

[philmoz]

New additions:

• QRCode widget (only available for Lvgl Lua scripts)
• Reduce memory overhead for stand alone Lvgl Lua scripts
• Allow widget option colors to use theme colors and properly update when theme is changed

For the last point, if a widget option is a color value, and the color value is chosen from the 'SYS' selection (or the default is a theme color), then it will be maintained as a theme color. It will automatically update when the theme is changed on the radio.

Note: for existing models and widgets the colors are saved as RGB values and will not be automatically changed to theme colors. The widget color options need to be edited and set to a 'SYS' color for this to work.

QRCode example:

[philmoz]

The changes to widget color options may fix issue #1151

[pfeerick]

LGTM. Can you update the demo script to your latest version (i.e. with the QR code).