SAML documentation corrections

[shawniverson]

Is some content missing, wrong or not clear?

The documentation for the following fails to mention that the AUTHENTICATION_PROVIDER has to be set to saml (lowercase) before SAML will work.

https://docs.open-metadata.org/latest/deployment/security/saml/azure

On step 4, it states "Set up for SAML is done, you should be routed to your IDP on trying to Sign-in." This doesn't happen until AUTHENTICATION_PROVIDER is set to saml.

https://docs.open-metadata.org/latest/deployment/security/saml/docker

The title of this article is "Keycloak SSO for Docker" but this isn't necessarily about Keycloak, which is in a different section of the documentation.

SAML_IDP_CERTIFICATE=/path/to/the/certificate

Using a path for this doesn't appear to work had to pass the entire certificate here as a string instead of the path to the file. When using a path it tried to parse the path as a base64 encoded cert instead of the contents.

Describe the solution you'd like
Update the documentation to mention need for AUTHENTICATION_PROVIDER and that the SAML_IDP_CERTIFICATE either needs to actually support a path in the source code or be updated to pass the certificate in as a string instead of a path.