Remove /admin route prefix

[JosephMarinier]

Description:

• Remove /admin route prefix in front of config routes. It didn't make much sense since getting the config is not really an "admin" action. In fact, the front end gets the config throughout the app.
• Fix duplicated front end cache tag

Checklist:

You should check all boxes before the PR is ready. If a box does not apply, check it to acknowledge it.

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• DEV CHANGES.
  • Update the documentation if this PR changes how to develop/launch on the app.
  • Update the README files and our wiki for any big design decisions, if relevant.
  • Add unit tests, docstrings, typing and comments for complex sections.

[gabegma]

Love it. While you are here - in test_routers, could you remove the annoying admin folder and rename the test file to test_config?

[JosephMarinier]

Totally! Good catch!