Add home button

Closes #27

See merge request Librem5/phosh!88

Just the button to spawn the favorites. Favorites, top anel rework will
be done separately (See #24, #29)

Closes: #27

The convention is to have the _TYPE_ after the prefix

Turn panel into a PhoshLayerSurface instead of open coding it

Closes #21

See merge request Librem5/phosh!87

Closes: #21

Introduce PhoshLockscreenManager

Closes #25

See merge request Librem5/phosh!85

This makes it configurabe via gnome-settings. But see #28 where this has
to go.

This is one open coded layer surface less and another part
of #21.

Closes: #25

This gives us better backtraces

Fix various potential crashers and make avoiding them simpler

See merge request Librem5/phosh!86

otherwise the unitialized variable might be cleaned up on the error
path.

Be pessimistic and assume failure when the pam handle did not get
cleanued up earlier.

Traces are still cut off

The files are even more imporatant then

We want to catch these early

Split Wayland registry code into separate class

Closes #26

See merge request Librem5/phosh!84

Split PhoshWayland out of PhoshShell where the former handles protocol
registration and the later all the surfaces and managers.

We can move PhoshShell into a separate file once we moved out the lock
screen handling to the lockscreen manager.

Closes: #26

Support org.gnome.Mutter.DisplayConfig.{Set,Get}CrtcGamma

Closes #13

See merge request Librem5/phosh!58

Only add outputs to the list of displays that are fully configured
(that received wl_output's done event). This prevents us to from
accessing half initialized monitors.

This allows us to listen for the done event.

This allows GNOME's redshift to work. Since wlroots gamma protocol
doesn't allow to read the gamma ramps fake empty ramps of the right
size. All users only use it to determin the gamma table's size.

Fixes #13

Use get_primary_monitor everywhere

Closes #20

See merge request Librem5/phosh!74

FIXME: check if we get the right widh/height after rotation

Closes: #20

Use valgrind in CI

See merge request Librem5/phosh!80

This will help us find leaks early