Marc: Form/Report As File, Path class, Config class, Typo3 v9 compatability

See merge request !296

# Conflicts:
#	extension/Classes/Core/Constants.php
#	extension/Classes/Core/Save.php

This fixes the current issue but is not a nice solution.
We just loop through all input elements having the same name.
It would be better, if we would filter out hidden elements.
But this might break some other behaviour... so I chose this approach.

B11666 trying to access array offset on value of type int

See merge request !294

# Conflicts:
#	extension/Classes/Core/QuickFormQuery.php

Fixes #10257. Delete AS _link only worked with certain parameter order.

See merge request !290

Fixes #7156 - Throw exception when a report level is defined twice.

See merge request !291

Fixes #11509. Implement a) detection of broken 'split PDF to JPEG', b) fire...

See merge request !292

Develop

See merge request !293

Fixes #11509. Implement a) detection of broken 'split PDF to JPEG', b) fire 'pdf repair'. Also implement configuration von 'convert' and 'pdf2svg'