Add application path as valid path for debuggers

Summary:
This will help applications to deploy (appimages, snaps, .zips) with debuggers
I have a windows deployment system with appveyor and drkonqi for windows and it's working without problems with a zip deployment and embedded cdb

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Reviewers: davidedmundson, tcanabrava, ngraham

Reviewed By: tcanabrava

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D19166