Add BeagleConnect C7 hardware graphics

See merge request docs/docs.beagleboard.io!43

SVG images from BeagleConnect C7 board schecmatic diagram.

Improving grammar and adding links to QWIIC/QT

See merge request docs/docs.beagleboard.io!42

Merge BeaglePlay and latest BeagleConnect documentation

See merge request !40

* Still need to fix references to git repos
* Still need to remove direct link to PDF schematic

Sorry to do this last second @lorforlinux, but I believe I'm making
things simpler. I hope I am!