Clearly mark the personalization plugins not to be "product-supported"

Apparently, the personalization components, built by the Ninja team back in the days, install dependencies on artifacts into a Hippo project, which are not maintained by brXM engineering (such as the hippo-addon-personalization, living in the prof serv GitLab group). We should be very explicit in Essentials that these plugins do not come with our usual maintenance and support guarantees.

In the future, this code may be taken over by the DXP Solutions team, but it is too early now to make such a decision / plan.