[FEATURE] Improve TCA API for detecting group field

The patch also does:

* Rename "relations" Grid Renderer
* Make distinction between text area and text field for editable content

Change-Id: Iadd72510533e6d8ffcc28d12598020f013544686
Releases: 0.2.0
Resolves: #52335
[TASK] Simplify grid view helper organisation

Change-Id: I95865fb4b864443a572fc1a168ee435f0448f034
Releases: 0.2.0
Resolves: #52336