Added start and end date optional params added to analytics endpoint

[UsmanDev09]

fixes #749

Description:

The endpoint analytics/[endpoint] now accepts startDate and endDate as optional params in ISO Date Time Format yyyy-MM-dd'T'HH:mm:ss. SSSXXX. I've added few checks too:

1. Start Date should be after 22 September, 2022
2. End Date cannot be in future
3. Either interval or start and end date can be provided, not both

P.S. Once the PR is merged, I'll update the docs and add an option in the UI to filter analytics by providing custom dates.