Quadcopter Workshop - Moved to lessons learnt

Started filling out lessons learnt and documentation for the quadcopter
workshop
Quadcopter Workshop - Added parts list
Quadcopter Workshop - ideas for future workshops
Quadcopter: tidied up parts list
Quadcopter - fixed up parts list filename
Quadcopter - more filename fixes
Quadcopter: add label for linking
Quadcopter: add link to parts list
merge quadcopter workshop stuff from upstream