Improving mobile/responsive screen view for admin

[kimcoleman]

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Changes proposed in this Pull Request:

A few tweaks to improve how our admin screens look on smaller screens and mobile. We could go farther with this, but the primary views are improved and really, the screens people need to use like

Other information:

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Changelog entry

• BUG FIX/ENHANCEMENT: Improvements to the plugin's admin area pages for mobile/responsive screens.

Enter a summary of all changes on this Pull Request. This will appear in the changelog if accepted.