Wiring the Spnego / Kerberos library packaged for Silverpeas.

Adding a new Groovy Script in order to update the configuration of SSO with Spnego/Kerberos already in place on Silverpeas servers.
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Don't forget to check:
- https://github.com/Silverpeas/Silverpeas-Parent/pull/24
- https://github.com/Silverpeas/Silverpeas-Core/pull/462