Disable OSDD Processing When SSO is Enabled

[marevol]

We're implementing a change to disable Open Search Description Document (OSDD) processing when Single Sign-On (SSO) is active. This adjustment is necessary to ensure seamless integration and functionality of our authentication system. Here are the key changes:

1. Introduction of a configuration parameter sso.type in FessConfig.java to manage SSO settings.
2. Modification of OsddHelper.java to conditionally disable OSDD based on the SSO settings.
3. Addition of constants AUTO and NONE in Constants.java to facilitate the new configuration logic.
4. Update of FessConfig.java and FessProp.java to support the new osdd.link.enabled logic, transitioning its default value from true to auto.

These modifications aim to enhance our software's authentication process by intelligently toggling OSDD availability in the presence of SSO.