[BUGFIX] Prevent attachment for empty files

Resolves: #58090
Change-Id: Ife9b961b7035ba52ed5d414aa197e8955459bfaa
[BUGFIX] Destroy session after submit

Resolves: #61146
Change-Id: I8b89b2fe5f494fd90c0213e297a7cec5633bd636
[BUGFIX]

Escape ' in Typoscript Setup for Javascript Variables (e.g. JsValidationCheckCheckboxes)

related: #61301
Version and manual update for 2.0.17 release
Merge branch 'develop'