Dev- Square Payment Gateway

[NirajChaudhary143]

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:

Previously, square payment integration is not available. This PR adds square payment gateway.

How to test the changes in this Pull Request:

1. You must active Ajax for square payment.
2. Make sandbox account. Sandbox Square
3. Create application account and test account.
4. Copy credential of Application account and enter on Everest Forms > Global Settings > Payments > Square
5. Watch Tutorial Tutorial
6. Note : At least one of given_name, family_name, company_name, email_address, or phone_number is required for a customer. So, map fields compulsory.

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 run tests with your changes locally?
• Have you updated the documentation accordingly?

Changelog entry

Feature - Square Payment Gateway

[joshianup1]

LGTM 👍

[riteelama]

LGTM 👍