Test for COG range requests

**Is your feature request related to a problem? Please describe.**
We recently published some COGs, but failed to validate if the range requests were supported. In the end the problem was caused by the firewall which didn't allow range request headers.

**Describe the solution you'd like**
Ability to run a series of range requests on a COG (cloud optimised geotiff). First request would fecth the index of the COG, then some requests to fetch some random data and see if a valid image stream is returned.