Migrate powerdevil keyboard shortcuts

Summary:
Powerdevil "faked" that it's name was "kded5" presumably as a way to
keep user's keyboard shortcuts without having to write a kconf_update
script.

It then tried setting the component name to "power management".
This fails because immediately after it does so, kscreen (which has the component name kded5
because it is in kded5) automatically changes the name back to "KDE Daemon".

This means two things:
- the shortcuts don't end up under their own "power management" section
in system settings properly.
- kglobalaccel5 on every startup thinks that the locale is changed (as
a component has changed name) and does some complex heavy writing which we don't want.

This patch moves everything to their own component, and provides a
kconf_update script to move shortcuts.

Test Plan:
Confirmed shortcuts moved
Confirmed we have our own "Power Management" section in systemsettings global shortcuts
No more writing on starting kglobalaccel5

I'd be grateful if someone else could confirm that migration works correctly. Migration is hard to re-test.

Reviewers: #plasma, apol

Reviewed By: apol

Subscribers: apol, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D9053