Port kcm energy info to kirigami 2, fix colors issues

Summary: Relates to D20533

Test Plan:
Before:
{F6775802}

After:
{F6920329}

Reviewers: ngraham, broulik, filipf

Reviewed By: ngraham, filipf

Subscribers: jbbgameich, filipf, davidre, broulik, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D20598