Manual.rst: updated to the latest autocron features.

Autocron: implement a) 'output to a file' (content of the retrived page), b) search for a pattern on the output.
Manual.rst: updated to the latest autocron features.

Change getMimeType() in Report in case file is missing or `file` beaks: instead to throw an exception, an empty string is returned.

Bug #5652 / TypeAheadSql: destroyed SQL statement. Fixed broken comparison and missing init of $sqlTest.

Session.php: After setting the QFQ cookie lifetime AND calling setcookie() after session_start(), the QFQ session remains. Also, skipping Session::clearAll() protects against broken SIP after logout!

AutoCron: Added doc for autocron. Extend AutoCron.php to be MultiDB aware. Update der AutoCron form.

Feature 4720 / Separate Database for Form & FormElement - Multi DB - fixed problem that 'Quick Edit Form / FormElement' has been broken in MultiDB Setup.

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=....

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.