Fixes #7682. 'Input textarea auto height' - Improve detection single/multiple lines, improve doc, enhance unit tests.

Fixes #1201. FE.parameter option has never been implemented. According https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/tabindex only the values '0' and '-1' are good. 'tabindex' has been removed from Manual.rst. FormEditor.sql has been changed that all links are 'tabindex="-1"'.

Refs #8204. Copy requiredPosition from Form to FormElement has been moved from 'formElementSetDefault()' to 'copyAttributesToFormElements()'

Fixes #7864. 'required'-FE Elements, deactivated via formModeGlobal=requiredOff, now gets class 'required-field'. The final 'required' mode is still temporarily disabled.

Refs #7743. Move error mesages to Constants.php. Unit tests use those constants now. 'data-pattern-error' only delivered if a 'pattern' is given. 'required' attribute only delivered is set.

FormElement.type=select: fixed problem with dynamic update and mode=readonly - list was still selectable.

Redesing FormEditor: FormElement as second pill. Hide MultiForm as long as it not active. Rename Various to Layout.

Fixes #7603: Unit test if DatabaseUpdate() plays well. Especially that formEditor.sql is running fine.

File not found in FE.type=file: Show more clearly that the pathfilename is only shown when ShowDebugInfo=on.

File not found in FE.type=file: Show more clearly that the pathfilename is only shown when ShowDebugInfo=on.

B3464: FE.type=subrecord, mode=readonly - fixed that sub form should be open with 'formGlobalMode=readonly'

Fixed broken init in phpunit run. Fixed access to uninitialized var. Throw exception if dndTable or form is missing.