* Remove pdfbox jars as they should no longer be needed.
* Reintroduce tests that use Tika to 'guess' mimetypes as it was the tika parse that was pulling in the pdfbox libraries.
Classes that use Tika:
* HTMLRenderingEngine - removed as it is no longer used
* RemoteConnectorResponseImpl - called tika utility toByteArray so not using pdfbox
* TikaCharsetFinder - called to identify the charset not mimetype so not using pdfbox
* MimetypeMap - main use of Tika. Used to detect mimetypes. Might have been using pdfbox.
Cherry pick from master (7.1.0)
