Request: Support additional prefixes/profiles in .properties- files

[valerakostin]

It would be nice to have a possibility to define properties with a custom prefix similar to platform specific values.

<LaF>.properties

# use 0 for Button.arc in Windows 10 or default value otherwise
[win10]Button.arc = 0
[win10]TextComponent.arc = $Button.arc

# Environment
[dev]Toolbar.background = @color1
[test]Toolbar.background = @color2
[prod]Toolbar.background = @color3

Use Cases:

• Windows 11 comes with the new rounded edges. There is no possibility to define different *.arc values for Win10 and Win11 in the same <LaF>.properties file.
• Customizing for different environment like dev, text, prod etc.