Currently this is all hardcoded in ProcessModel. By moving it into a
plugin we can make that model half the size.
Code is ported to use libTM instead of KWindowSystem for a few reasons:
- It works on wayland (assuming we have the extra permissions set)
- We get to make use of the more complex advanced mapping in libTM
- It has fixed code to get the right PID for a window so apps in a PID
namespace have the icon in the right place (currently broken in
ksysguard)
Requires some tiny mods in ProcessModel to map the decoration role.
Introduces a p-w dependency in ksysguard, but not the lib so there's no
lib.