Landsat Pre-Collection depreciated - Welcome Landsat Collection 1

[vincentsarago]

per sat-utils/sat-api#12 Landsat Pre-collection is depreciated since April 30. The csv

landsat8-metadata/reader.py

Line 51 in 6557d95

url = 'https://landsat.usgs.gov/landsat/metadata_service/bulk_metadata_files/LANDSAT_8.csv'

doesn't seems to be relevant anymore.

We should switch to https://landsat.usgs.gov/landsat/metadata_service/bulk_metadata_files/LANDSAT_8_C1.csv.gz

more info : https://landsat.usgs.gov/download-entire-collection-metadata

but as it's a .gz some work need to be done. Also maybe some refactoring need to be done on the database and the API.

cc @matthewhanson @drewbo @scisco