feat(addon-viewport): editable width/height

[AndrewLeedham]

This is still a WIP.

Issue: #12586

What I did

• Added a NumericInput component to @storybook/components
• Used the new NumericInput in place of the width/height labels in the @storybook/addon-viewport toolbar.
• Adjusted the way styles are applied from the @storybook/addon-viewport plugin, to work with the new inputs.

How to test

• Chromatic screenshots for the NumericInput.

[stale]

Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 30 days. Thanks!

[AndrewLeedham]

Still a WIP, just haven't found the time to finish it off.

[stale]

Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 30 days. Thanks!

[ndelangen]

@AndrewLeedham I'll close the PR for now. If you're able to work on it again, we can re-open.

Thank you for the time and effort you've put into this.