Add button on Settings Page to clear entire Redis cache

[mcverter]

Fixes # (issue)

Feature Request: UI to clear Redis cache
#2276

Description

Adds a second button below the "Clear Organization Cache" that completely wipes out the Redis Cache.
This functionality is limited to those who have admin permissions.
Let me know if either the permissions or the erasure of cache values should be further limited.

Checklist:

• I have manually tested my changes on desktop and mobile
• The test suite passes locally with my changes
• If my change is a UI change, I have attached a screenshot to the description section of this pull request
• My change is 300 lines of code or less, or has a documented reason in the description why it’s longer
• I have made any necessary changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• My PR is labeled [WIP] if it is in progress