feat(port): add plasma

[Unkn0wnCat]

Description

This PR adds a port for KDE Plasma containing two .color-files for native use with the plasma desktop environment.

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• [x] PR description included
• [x] I've read the documents
• [x] I've created or commented in an issue related to this port asking to work on it (#88)
• [x] I know I shouldn't change any files in the packages folder manually
• [x] I've added this port at the end of the related category list in the main README
• [x] I've attached an image to the icon of the app that this port is related to
• [x] I've attached a screenshot with a good zoom in fullscreen showing this port in action

[daltonmenezes]

Well done @Unkn0wnCat , thank you so much for your contribution. 💜