Description of the new feature/enhancement

We'd like to add Base layer back into the settings UI along with an Extensions page to help avoid the conflicts between profiles.defaults and JSON fragment extensions.

The Extensions page will take some time to design, but we'd like to get started with getting Base layer back into the UI, so we'll track the progress on the Extensions page in another issue.

For now, let's add Base layer back into the settings UI with the following improvements:

• Change the name Base layer to Defaults
• Add the Defaults page back into the settings UI
• Add the reset buttons back into the profile pages
• Collect data on which settings are applied using Defaults
• Collect data on how often the profile page reset buttons are used

Related: #9539

Proposed technical implementation details (optional)