Port away from KHTML

Summary:

• Port glossary to QTextBrowser: Straight forward part with just exchanging KHTML functionality with

QTextBrowser, resulting in same results.

• Port detailed information to QTextBrowser: Visual changes are small. This change also puts the general information

into the header to avoid visual inconsistencies between different
pages.

• Remove KHTML Dependency: This patch also makes all implicit KF5 dependencies visible that

were pulled in via KHTML.

Reviewers: KDE Edu, apol, yurchor

Reviewed By: yurchor

Subscribers: yurchor, aacid, kde-edu

Tags: KDE Edu

Maniphest Tasks: T11572

Differential Revision: https://phabricator.kde.org/D23830