Implement bbs_database download for biorxiv and medrxiv

[jankrepl]

Fixes #512

Description

Implements the download logic for biorxiv and medrxiv.

How to test?

Note that the entrypoints will ask you to enter the credentials!

To run the dry run

bbs_database download medrxiv -n 2021-10 output_folder

To run an actual download

bbs_database download biorxiv 2021-10 output_folder

Checklist

• This PR refers to an issue from the issue tracker.
  (if it is not the case, please create an issue first).
• Unit tests added.
  (if needed)
• Documentation and whatsnew.rst updated.
  (if needed)
• setup.py and requirements.txt updated with new dependencies.
  (if needed)
• Type annotations added.
  (if a function is added or modified)
• All CI tests pass.

[Stannislav]

When I try the dry-run example it sill asks me for my AWS credentials and when I enter random characters I get the (expected) error:

botocore.exceptions.ClientError: An error occurred (InvalidAccessKeyId) when calling the ListObjects operation: The AWS Access Key Id you provided does not exist in our records.

Is it possibly to do a dry-run without credentials or not at all?

[jankrepl]

When I try the dry-run example it sill asks me for my AWS credentials and when I enter random characters I get the (expected) error:

botocore.exceptions.ClientError: An error occurred (InvalidAccessKeyId) when calling the ListObjects operation: The AWS Access Key Id you provided does not exist in our records.

Is it possibly to do a dry-run without credentials or not at all?

Unfortunately, you have to have the credentials even for the dry run. Why? Well, to do the dry run one needs to send a request to the AWS server and that requires authentification.