Switch to api.openstreetmap.org API host

[danieldegroot2]

Use api.openstreetmap.org/api/ -and HTTPS- instead of www.openstreetmap.org/api/*.

(Is: openstreetmap/operations#951)

Note, api.openstreetmap.org API url currently can not do OAuth 2 handshake. See openstreetmap/operations#951 (comment)
You can split the www. base URL and api. API url. See osmlab/osm-auth#123 (comment)

See also osmlab/osm-auth#123 (comment) for another solution.

• Update production URL documentation
• Update authentication URL as needed.

Was: #8

(Maintainers can edit this post to update the to-do list.)