Summary:
Compile without casting to/from ascii to avoid typical mistakes due to
implicit conversions. Fix a bunch of dubious places.

Test Plan: Things compile, tests run.

Reviewers: #plasma, davidedmundson

Reviewed By: #plasma, davidedmundson

Subscribers: zzag, anthonyfieroni, broulik, davidedmundson, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D14060

Summary: BUG: 386900

Test Plan:
Ran plasma on wayland in virtio, instead of switching to 4096x2160@60
it stays at the right resolution of 1024x768@60 on startup and kscreen-doctor
shows that it's indeed set as the preferred mode.

Reviewers: #plasma, sebas, graesslin

Reviewed By: #plasma, graesslin

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D8828

The correct category to use is kscreen.kwayland, not kscreen.wayland.

This merges the kwayland backend into libkscreen master.
In this particular commit: more stylistic improvements

REVIEW:126381

...to make sure the checked test are in line with what we expect.

These currently fail, they reveal a problem with the id mapping between
wayland and kscreen ids that I'll fix separately.

This test adds and removes an output and watches config changes. The
changes are propagated, but the output list isn't updated properly.

Also kill unused headers

Add a few tests to find out when exactly we're creating new config (or
when we should do that)

Only run one config file for now, we'll need to figure out how to make
the whole restarting logic work better, but it's not a common usecase,
so low priority for now.

This reflects that it's based on KWayland, and supposed to be used with
that library, it's not a generic backend yet, since it uses a
not-yet-upstreamed protocol.

Instrumentation to measure performance differences between runs.

Not just against enabled ones. This makes the test fail, it will pass
once the disabled outputs have been implenented in WaylandConfig.

- server code is now shared with tests/waylandtestserver
- test physicalSize()
- test output properties

Each individual test succeeds, but running all three config files after
each other doesn't work yet.