Add /count to more endpoints

[abbycabs]

Add documentation for:

• [x] /users/:orcid/badges/count
• [x] /papers/:doi1/:doi2/badges/count

Places to implement /count (& document):

• [ ] /badges/count
• [ ] /badges/:badge/count
• [ ] /users/:orcid/badges/:badge/count
• [ ] /papers/:doi1/:doi2/badges/:badge/count
• [ ] /papers/:doi1/:doi2/badges/:orcid/badges/count
• [ ] /papers/:doi1/:doi2/badges/:orcid/badges/:badge/count

[josmas]

all merged as per #190; closing this issue now.