Harvesting through Timestamp

[bhavin2897]

OAI-PMH harvester (py3 branch) really works fine and I have no issues.
Yet it would be great to incorporate Timestamp harvesting, using from and to just like API requesting via https URL.
This would really help and make things easier.

You have already provided:
1.username and pwd
2.metadata_prefix
3.set
4.force_http_get

Just like above, it would be interesting and effective if the user can harvest datasets between a timestamp.
example: the user can add in the configuration text as
"from" : 2020-10-10
"to" : 2021-09-22

Looking forward to your response and update if possible.