Add support for the downloading of L2A products
L2A products should be downloaded directly if they exist on the server (optional for the user).
The processed L2A product's identifier is different from the L1C product's identifier. Therefore, the key linking every L1C and their processed products (L2A, indexes) can't be the identifier anymore but only the tile and the acquisition time.
This issue will be resolved with #2 (closed)
Edited by Jeremy Commins