Enhancement - Date time slot booking

[MILAN88888]

All Submissions:

• Have you followed the Everest Forms Contributing guideline?
• Does your code follow the WordPress' coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

This PR adds the new slot booking feature in date/time field.

How to test the changes in this Pull Request:

1. Edit or create a form then drag the date/time field.
2. Goto the field option -> check the slot booking option in the advanced setting.
3. Submit the form by choosing a date. and again try to submit by choosing the exact date. verify the message and repeat the process for different formats and modes of date/time.

Types of changes:

• Bug fix (non-breaking change which fixes an issue)
• Enhancement (modification of the currently available functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you successfully ran tests with your changes locally?
• Have you updated the documentation accordingly?

Changelog entry

Enhancement - Date time slot booking

[dipuchaudhary]

LGTM 👍

[salimshrestha98]

LGTM !! 👍

[deepench]

LGTM 👍