Feature : Let user export mapper information on exports

[kshitijrajsharma]

What does this PR do ?

• Lets logged in user make exports with mapper information ( i.e. username and uid)

Consideration

Only the User with openstreetmap account can do this , For user with no login this option is forbidden . Usually this is the same way how geofabrik lets visitors to download the data and so does the OSM

How to test ?

• A new param should be available on the API it should throw insufficient user info if user is not logged in !