Default module variables to `protected`

[MicEsp22]

Allow for defaulting module variables to protected:

module <ModuleName>
   [<use statements>]
   implicit none
   protected         ! Currently only  public/private
   
   [...]
end module [<ModuleName>]

In such a case, protected access specifier would imply default public visibility for procedures/interfaces/DTs defined within the same module.