CKEditor and more: Use ck-content class for displaying content + other bugfixes

[blackcoder87]

Description

We didn't use the "ck-content" class when outputting content created in the CKEditor. This caused the output to look different from what the user entered in the CKEditor. Fixed various other errors which I noticed while working on this.

• Added the "ck-content" class for the content that was created in the CKEditor.
• ilch.css: set "overflow: auto" for ck-content or otherwise it would affect everything after the "ck-content" div.
• Contact: Removed required attribute for the textarea used by CKEditor as it doesn't work with CKEditor 5.
• Rule: Fix "Invalid argument supplied for foreach() in application/modules/rule/views/admin/index/treat.php:52".
• Newsletter: Remove unsubscribe link from show action.
• Newsletter: Remove email from unreadable link.
• Teams: Fix error with no leader or coleader.
• War: Fix invalid group image error.
• War: Fix error when trying to add a map.
• War: The matchtype couldn't be entered when trying to add a war.
• HTMLPurifier: Added a unit test for "Wrap text: Left aligned image".

Fixes #1150
IlchCMS/Ilch-2.0-Module-Checkout#7
kveldscholten/kvticket#7

Before

After

ToDo

• admin
• article
• calendar
• checkout
• checkoutbasic
• contact
• events
• faq
• forum
• guestbook
• history
• imprint
• jobs
• newsletter
• privacy
• rule
• shop
• teams
• training
• user
• war
• application/libraries/Ilch/Comments.php
• ...

External

• kvticket
• kvteam
• radiohoerercharts ?

Type of change

• Bug fix (non-breaking change which fixes an issue)

This PR has been tested in the following browsers:

• Chrome
• Firefox
• Opera
• Edge

[blackcoder87]

Gibt es beim Hinzufügen der "ck-content"-Klasse Einsprüche? Wenn nicht, dann würde ich das so mergen und auch einen PR für kvticket erstellen.