Use colorful icon for "Profiles" in settings window sidebar

Summary:
This is in support of T10165 specifically, and Goal: Consistency more generally.

The chosen colorful icon for the Profiles page isn't perfect, but I think it's better
than what's there right now.

Test Plan:
Before:

Reviewers: VDG, Konsole, GB_2

Reviewed By: VDG, GB_2

Subscribers: ndavis, GB_2, konsole-devel

Tags: Konsole

Maniphest Tasks: T10165

Differential Revision: https://phabricator.kde.org/D24273