Add an iterator which wraps endpoint search
Add an iterator which wraps endpoint search

The iterator walks over the results, yielding them, until
`has_next_page` comes back on the response as false.

globus/globus-sdk-python,aaschaer/globus-sdk-python,sirosen/globus-sdk-python,globus/globus-sdk-python,globusonline/globus-sdk-python