Multi-tenancy support for adding logos

When there are different tenants on the same server, you can add different logos for each one. The attribute tenantId is stored in the session.

The default tenantId is /pentaho/tenant0. The Change Me! logo image is stored in /pentaho-server/pentaho-solutions/system/pentaho-interactive-reporting/resources/images/pentaho/tenant0 with the nameLogo.png. When you have multiple tenants, each tenant is represented by a folder with a unique tenantId in place of "tenant0". Each tenant folder must contain the logo of the respective tenant named Logo.png.