Move qt plugin from qtubuntu-sensors here and remove use of platform-api client

Move qt plugin from qtubuntu-sensors here

This also removed the use of platfrom-api client in the qt plugin, this makes it much cleaner and removes the need for the hacky dload methods that platform-api uses. Should be more stable with less crashes

Note that trust-store is still broken so testing needs to be done with that disabled (or run the app from cli)

Fixes: #10 (closed)