Admin components clean (without sidebar)

[hazeltonbw]

Description

This PR removes the manage users button from the admin panel. This PR also includes changes to the admin panel as discussed in weekly meetings with @huss.

1. Remove Manage Users button from Admin Panel
2. Organize settings into their own categories, and give each a header to make it easy for the user to find the settings they want
3. Change "Default site title" to "Site title"
4. Rename Admin Panel to Admin Settings
5. Update/add translations
6. Small CSS tweaks

Partially Addresses #890

Type of change

• Note merging this changes the database configuration.
• This change requires a documentation update

Checklist

• I have followed the OED pull request ideas
• I have removed text in ( ) from the issue request
• You acknowledge that every person contributing to this work has signed the OED Contributing License Agreement and each author is listed in the Description section.

Limitations

This PR will not be necessary if PR #1316 (Admin Settings w/ Sidebar change) gets merged as it changes the admin settings page completely.

[huss]

This is to note that this PR should not be merged until PR #1306 is merged. This is due to the fact that the user button is (correctly) removed from this page in anticipation of the new user page/modals.

[huss]

Thanks to @hazeltonbw for this contribution. I've made a couple of comments to address but overall this looks good.

[huss]

Thanks for the update to address the comments. Overall, this looks good. I made a couple of comments that I think should not be hard to address.

[huss]

Thanks to @hazeltonbw for the quick changes and taking the time to address everything instead of a future issue. This works as expected and is ready to merge.