NIM: Missing `client_key` and `client_secret` in OIDC Configuration

[travisamartin]

Issue

The NGINX Instance Manager documentation for setting up OIDC authentication with Microsoft Entra ID contains an incomplete configuration example in the openid_configuration.conf file. The provided example does not reference {client_key} or {client_secret}, making it unclear where users should set these values.

Affected Document

Microsoft Entra: Set up OIDC authentication

Expected Result

The openid_configuration.conf file example should include all necessary configuration directives, such as {client_key} and {client_secret}, with placeholders indicating where users should insert their specific values. This ensures users can accurately configure the file without ambiguity.

Updating the documentation with a complete configuration example will help users set up OIDC authentication correctly, reducing potential errors.

[mjang]

Supersedes #234