Add BeagleConnect & BeaglePlay demos page

See merge request docs/docs.beagleboard.io!46

Update BeagleConnect graphics & Add tag-connect under accessories

See merge request docs/docs.beagleboard.io!44

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