[TASK] Writing documentation

Add some description of the attributes of field types.
Add information about user conditions.

Resolves: #58535
Releases: 6.2, 6.1, 6.0, 4.7, 4.5

Change-Id: I2f482bed91935e3f76c2e4a7f69b9f4e19cee91d
Reviewed-on: https://review.typo3.org/30337
Reviewed-by: Armin Ruediger Vieweg
Tested-by: Armin Ruediger Vieweg
[TASK] Writing documentation

Add an important hint, when using DCE content elements in other DCEs.

Relates: #58535
Releases: 6.2, 6.1, 6.0, 4.7, 4.5
Change-Id: I7e6301eb6bb3cea7696786acb94596159353ddaf
Reviewed-on: https://review.typo3.org/30396
Reviewed-by: Armin Ruediger Vieweg
Tested-by: Armin Ruediger Vieweg
[TASK] Writing documentation

Some updates

Relates: #58535
Change-Id: I80ddcfeb05388124a324dc27f78f62348490c27b
Reviewed-on: https://review.typo3.org/31072
Reviewed-by: Armin Ruediger Vieweg
Tested-by: Armin Ruediger Vieweg
Merge branch 'classic-documentation'

Conflicts:
	Documentation/AdministratorManual/Index.rst
	Documentation/Images/Tutorial/fieldDescription.png
	Documentation/Images/Tutorial/fieldGalleryName.png
	Documentation/Images/Tutorial/fieldPictures.png
	Documentation/Images/Tutorial/newDceGalleryElement.png
	Documentation/Index.rst
	Documentation/Introduction/Index.rst
	Documentation/Settings.yml
	Documentation/UserFaq/Index.rst
	Documentation/UsersManual/Index.rst

Change-Id: I427b19df7fa790c8ef4e72cbcca1121e1d137e33