Improve timeline clips color palette
This is a proposal to improve the timeline clips colors.
Here is a draft to build on:
Bonus:
- Make the audio waveforms clearer.
- Add ability to color tag clips.
See here for more info: https://phabricator.kde.org/T10085
https://community.kde.org/SoK/Ideas/2020#Project:_Promo.2FKdenlive