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* ZendPdf seems to be very picky about PDFs and is no longer maintained,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!
So, just adding to the extension root composer.json file will download its dependencies on EM install? Is that already the case?  

I thought currently composer support is only ready for the CMS itself, not for extensions (even tough I've noticed some work regarding this effort - especially the PackageState file.) Any inside read for this?