Feature #5571 / File Upload: save filesize and mimetype automatically in 'upload mode simple',if those columns exist.

- STORE_VARS contains now 'mimeType' and 'fileSize'.
- sqlBefore and sqlAfter will be fired in Upload Advanced and new in Upload Simple as well.
- STORE_VARS contains now `filenameOnly`. It can be used in downloadButton=....

# Conflicts:
#	extension/qfq/qfq/database/DatabaseUpdateData.php

Bug: Form: 'FormElement' > 'Container' - relied on '{{formId:S}}' even if the FE record already exist - fixed

Feature 5425 / thumbnail: rewrite - secure thumbnails are now rendered on first access, not when 'AS _thumbnail' is called.

#5367 / Error Report: 'full level' missing: still miss when UserReport Exceptions are thrown - fixed