"Software not found" Runner

[Aleix Pol]

Hi,
Last week I put together this runner, thought it might be useful, so
if you type in krunner an application but it's not installed, it will
offer to open Discover to install it (any software center in fact).

Do we want to push this for the next plasma release?
If so, do we want it enabled by default?

You can look and test here:
https://quickgit.kde.org/?p=scratch%2Fapol%2Fappstreamrunner.git

Cheers!
Aleix