Code cleanup on the Profile Settings

Summary:
Favor manual list creator over for loop for small list

Three items, create them manually, cleaner and less
computationally expensive.

Btw - this is ugly, both ways. I blame QStandardItemModel.

Simplify Logic

Use auto when types are explicit

Simplify Logic: use ternary when it improves readability

Stack when heap's uneeded.

There's absolutely no point on creating a QPointer
and manually deleting the item later. Just create
the variable on the stack

Auto when type's explicit

Subscribers: konsole-devel

Tags: Konsole

Differential Revision: https://phabricator.kde.org/D13532