[Linter] Report a warning when a field's access is constant, public, and the type mutable

[turbolent]

Issue To Be Solved

It's a bad practice and often unintentional to expose mutable state indirectly by having a constant field which is public, and the type is mutable.

Eventually we might want to forbid this, i.e. make it an error.

Suggested Solution

• Report a warning when a field is constant, public, and the type mutable