add UKUI desktop environment icons

[hantengc]

1. optimize icon acquisition logic to prepare for customizing icons for other desktop environments in the future
2. add function for judging the ukui desktop environment
3. add UKUI desktop environment icons

[CoelacanthusHex]

Shouldn't this thing be controlled by modifying the input-keyboard icon in the icon pack?

[hantengc]

@CoelacanthusHex 1. Not sure if there are any other packages that use the input-keyboard icon, changing the system icon name will have other effects
2. In the past, I used to use icons for the KDE environment, but I think I could add icons for other desktops as well

[wengxt]

I'm not sure if english us is the icon you want.

When this icon is used, it doesnt have to be English US

[hantengc]

@wengxt It means that other layout input methods are also using this icon, right? Then I should have our UI designers design a more generic icon