Add shortcut to the editor toolbar

[IceQ1337]

The wysiwyg-editor shortcut should remove the hassle of figuring out the timestamp for a certain datetime. Instead, the user should be able to simply select a date and specify whether they want a fixed or relative time view.

Additionally, clicking on the toolbar with an active selection could simply enclose the text (ideally a valid timestamp) with the BBCode.

• Add typescript module to change default behaviour of the bbcode button
• Add current timestamp when clicking the toolbar button without active selection
• Wrap tags around current selection
  • WoltLabs implementation is (seemingly) insufficient in providing necessary information, so this has to be done manually.
  • The editor holding all the information is not accessible at all and there is no information about the selection (range/offset)
• Open popup to select a datetime and insert its timestamp into the editor (with tags)
• Add formatting options to the popup

The popup might require a separate ckeditor-plugin implementation, which is out-of-scope for this plugin. I can think of an implementation via dialog instead. Not so intuitive, but implemented quite quickly.