Add: TermPicker Component

[xavortm]

Description of the Change

Adds new Terms Picker component to allow editors to pick a single category from set of categories. There is similar existing component in core https://github.com/WordPress/gutenberg/blob/trunk/packages/editor/src/components/post-taxonomies/hierarchical-term-selector.js but it is a checkbox instead of radio picker.

More info TBA;

Closes #81

Alternate Designs

Possible Drawbacks

Verification Process

Checklist:

• [ ] I have read the CONTRIBUTING document.
• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my change.
• [ ] All new and existing tests passed.

Changelog Entry

Credits

Props @