FEATURE: Proper inline mode (autoparagraph "false")

[mhsdesign]

Description

CKeditor doesnt offer a "real" inline mode currently ckeditor/ckeditor5#762 but we can improve our implementation by https://stackoverflow.com/questions/48896019/ckeditor5-inline-build-puts-a-p-tag-inside-of-an-h1-tag-how-do-i-disable-this/49130552#49130552

This would fix following issues:

• Edit: might be fixed with BUGFIX: Fix ckeditor inline mode autoparagraph: false #3532: When you paste text with newlines, they will be turned currently into a bunch of spans but there are no breaks (br)
  • input foo\nbar -> expected foo<br>bar actualy <span>foo</span><span>bar</span>
• it is possible to have multiple root elements like after pasting or when the ckeditor is booted with <p>foo</p><p>bar</p>
  • this was previously for a long time really buggy and you would get invalid html BUGFIX: Fix ckeditor inline mode autoparagraph: false #3532
• you use the heading formatting, which makes no sense on an inline editor, as it should produce contents without outer tags.
• our super hacky code to not produce outer tags BUGFIX: Fix ckeditor inline mode autoparagraph: false #3532 can be cleaned up
• we can fix Bug: Ckeditor Plugin: this.editor.neos.contextPath is not available during plugin init()  #3223 while we are at it (because we need to extend the editor and will do our own construction phase)
• autoparagraph "false" is currently not the best naming for what we actually need, so this will be for legacy behaviour but we can deprecate it and add a isLimit or isInlineMode like this...
• further we should define who determines the inline mode. Is it the yaml config or the block: false from the Neos.Fusion:Editable?

[mhsdesign]

Also the behavior, as it might depend on the rendering of block = false is different in a richtext editor on the side.