add args in opts_environment() to display more, or less, with `.env()`

[moodymudskipper]

.env() uses non functional args to display "parents", attributes (incl "class"), and "locked"

We could use it to display more, for instance display the name of the objects, or even their full construction, and we could also optionally reconstruct the parent itself.

This way it might look a bit like using the list approximations but keeping an exact construction.

We could have context = c("parents", "attributes", "locked) where context can also contain : "parent", "objects", and "names"