Dolphin Service Menu Installer: Launch certain scripts in Konsole

Summary:
In general the issue with installers/uninstallers for the dolphin plugin is
that a lot of the scripts are intended to be run manually in a terminal.
For instance if a script uses sudo make install the user can't type in the password.

With this patch scripts that are executed without arg variants are
executed in konsole (if available).

Test Plan:
Tests still pass. Try to install the "Jetbrains Dolphin Plugin" tar.gz file from the kde store.
If you have the required dependencies etc. the konsole window should close.
If the install script fails (type in wrong admin password a couple of times) you
should have a shell opened.

Reviewers: Dolphin, ngraham, nicolasfella, elvisangelaccio, meven

Reviewed By: Dolphin, elvisangelaccio

Subscribers: kfm-devel

Tags: Dolphin

Differential Revision: https://phabricator.kde.org/D29089