Fix formatting and add ascp password env variable

There were a few problems with the new configuration that we got after
contacting EBI, in short:
    - Passwords had to be updated, so we've centralized the retrieval of
      the credentials to be only in this file for the subprocesses that
      need them.
    - There was a missin `"` in the formatting of a string to generate
      the CURL commands.
Remove "legacy" white spaces

These are not needed for anything.
Merge pull request #638 from ElDeveloper/ebi-improvements

Fix formatting and add ascp password env variable