[COG] Media type

[Matthias Mohr]

Dear all,

the GeoTiff SWG decided on a media type for GeoTiff: image/tiff; 
application=geotiff
See 
https://github.com/opengeospatial/geotiff/issues/34#issuecomment-514078289

Based on the assumption that IANA accepts it, I'm wondering whether COGs 
could also get a recommended media type now.

Two proposals from my side:
- image/tiff; application=geotiff; cloud-optimized=true
- image/tiff; application=geotiff; cog=true

What do you think?

Having a recommendation would be very helpful for STAC and openEO, for 
example.

Best,
Matthias