feat(core/icon-button): implement a11y features for icon-button

[jg0815]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (yarn build) was run locally and any changes were pushed
• Unit tests (yarn test) were run locally and passed
• Visual Regression Tests (yarn visual-regression) were run locally and passed
• Linting (npm lint) was run locally and passed

Pull request type

Please check the type of change your PR introduces:

• Bug fix
• Feature
• Refactoring (no functional changes, no API changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the new behavior?

• Implemented new property 'ariaLabel' for the icon-button component, which is required as an accessibility label for the respective icon used.
• Implemented the required ARIA-attribute settings for the icon-button component (aria-label).
• Implemented fallback icon lables based on the icon names from the iX-build-in icon library (EN-language only).
• Added required attribute 'disabled' for the <button> element.

Does this introduce a breaking change?

• Yes
• No

Testing

Other information

[nuke-ellington]

@jg0815 question regarding label name in review comment