3393 credential pairs configuration

[ordabach]

What does this PR do?

New propagation's page of the credentials configuration

PR Checklist

• Have you added an explanation of what your changes do and why you'd like to include them?
• Is the TravisCI build passing?
• Was the CHANGELOG.md updated to reflect the changes?
• Was the documentation framework updated to reflect the changes?
• Have you checked that you haven't introduced any duplicate code?

Testing Checklist

• Added relevant unit tests?
• Do all unit tests pass?
• Do all end-to-end tests pass?
• Any other testing performed?

  Tested by {Running the Monkey locally with relevant config/running Island/...}

• If applicable, add screenshots or log transcripts of the feature working

[mssalvatore]

I was able to add a row that had a public key but no private key.

[mssalvatore]

We need a way for the user to be able to "unhide" the secrets in the rows so they can see what's actually in the table.

[mssalvatore]

The "Add New credentials" box kind of blends into the table and looks like a header row or something. Can we just make it so it doesn't collapse?