Make values for web-ui.authentication.type case insensitive

[mosabua]

Currently only lowercase works .. however this is inconsistent with http-server.authentication.type which we actually document in all uppercase for some reason but we are forcing it to lowercase and actually support using either.

We should do the same for web-ui.authentication.type so that uppercase and lowercase and so on works just fine.. and then as a follow up maybe decide how to update the docs so it is also consistent..