Issue/cif 2202

[pawan-mittal]

Summary
The purpose of this PR is to add CSS styles for virtual and combined gift card forms.

Description

This PR includes virtual and combined gift card form CSS styles using BEM notation.

Related Issue

CIF-2202, CIF-2200, CIF-2199

Motivation and Context

The purpose of this PR is to show the gift card form with styles on the PDP page, matching with the Magento gift card form

How Has This Been Tested?

Tested in the context of the cif core component examples

Screenshots (if appropriate):

Types of changes

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

Checklist:

• I have signed the Adobe Open Source CLA.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes and the overall coverage did not decrease.
• All unit tests pass on CircleCi.
• I ran all tests locally and they pass.