feat(variable-binding): Adding the sling models for variable bindings

[DhruvSharma-845]

Description

Related Issue

Motivation and Context

How Has This Been Tested?

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.

[codecov]

Codecov Report

❌ Patch coverage is 68.29268% with 13 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ore/components/util/AbstractFormComponentImpl.java	71.87%	5 Missing and 4 partials ⚠️
...s/core/components/models/form/VariableBinding.java	0.00%	4 Missing ⚠️

📢 Thoughts on this report? Let us know!

[adobe-bot]

Accessibility Violations Found

Id	Impact
aria-required-attr	critical
empty-heading	minor
label-title-only	serious
target-size	serious

[adobe-bot]

Accessibility Violations Found

Id	Impact
aria-required-attr	critical
empty-heading	minor
label-title-only	serious
page-has-heading-one	moderate
target-size	serious

[adobe-bot]

Accessibility Violations Found

Id	Impact
aria-required-attr	critical
empty-heading	minor
label-title-only	serious
target-size	serious

[adobe-bot]

Accessibility Violations Found

Id	Impact
aria-required-attr	critical
empty-heading	minor
label-title-only	serious
target-size	serious