Decide on additional pointer annotations especially for parameters

[robertmuth]

For optimization and correctness purposes, it would be nice to have more information about pointers, e.g.:

• is a pointer argument unaliased during the life of a function call (similar to "restrict")
  Note: we have similar attributes for FunParam: arg_ref, res_ref in
• is a function allowed to create aliases of parameters and/or allowed to store it into into the heap

TODO: add some links to literature here