This adds a way to define a way, at the system level, to define a policy
of how monitor configuration files are loaded.
The intended use case is to e.g. either prefer system level monitor
configurations before user levels, or only allow system level
configurations.
Examples:
Prefer system over user level configurations:
<monitors version="2">
<policy>
<stores>
<store>system</store>
<store>user</store>
</stores>
</policy>
<configuration>
...
</configuration>
</monitors>
Only allow system level configurations:
<monitors version="2">
<policy>
<stores>
<store>system</store>
</stores>
</policy>
<configuration>
...
</configuration>
</monitors>
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2030>
It tests that if we go from (x is the pointer cursor)
+--------+
| |
| X |
+--------+
to
+----------------+
| |
| |
+--------+ |
| | |
| X | |
+--------+----------------+
i.e. making sure that X ends up somewhere within the logical monitor
region.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2237>
