Issue-3: Add \"before\" and \"after\" date parameters

[renatonascalves]

Summary

Fixes #3

This pull request addresses the issue where it isn't possible to pass a date query via a flag argument. It introduces --start-date and --end-date flags that map to a date query, making it easier to filter posts or audits by a specific date range.

Motivation

Previously, users could not easily filter results by date using flag arguments, which limited the ability to generate audits for specific time periods (e.g., posts published in the last 12 months). This change improves usability and addresses a recurring user need.

Test Plan

• Verify that passing --start-date and --end-date flags filters results as expected.
• Test various date ranges and ensure the correct data is returned.
• Ensure backwards compatibility with existing commands.

Checklist

• Tests added or updated
• Documentation updated (if needed)
• Verified against requirements in the related issue