User Notes used for security information needs capability to be searched

[wangf1122]

This is specifically for our internal (DFO) project user. Not sure if anyone else will need it. We do store security information into this field

But this fields does not return into the search result. It is not part of the gn4 elastic search capability. So just wondering if there is a dynamic way to config it.

I have created two PR to add it, it's static way to add them. Not the dynamic configuration. But if there is configuration way to have it into the search, it will be better. Here are the two PRs:

geonetwork/core-geonetwork#8004

#380