PR 32097

Added image and pdf extraction.

Facts and todos:

* Need to add TCA definitions
* This uses PHP functions only, no support for third party tools
* This extracts the most common exif and ipct data from images
* Currently no support for XMP data
* Think about normalizing city and country codes by using static_* data
* ZendPdf seems to be very picky about PDFs and is no longer maintained,
	but I  found no good alternative (except pdfpasrer but its about 30mb)

We could squash some commits to have a nicer merge late ron. Please give some feedback!
...and move the call of this method where currently the variable is checked (so within extractExifMetaData)? 

I was not sure if the extractor is called as an singleton or a new instance is created for each processed file. Wanted to prevent that these tests will be called every time.