Update Deployment files

Summary:
We would like to have an appimage at some point for this we need to make sure that our desktop has no warnings or errors. Our flatpak's description has also been improved.

• Remove warnings from desktop file
• Update description in appdata

Reviewers: Atelier, laysrodrigues

Reviewed By: Atelier, laysrodrigues

Subscribers: Atelier

Tags: Atelier

Differential Revision: https://phabricator.kde.org/D13799