debugger: DataLocation is deprecated, move to AppDataLocation

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

debugger: Use a stringlist to search in different paths for debugger configuration files

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

Reviewers: mart, davidedmundson

Reviewed By: davidedmundson

Subscribers: plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D17024