Add opam package for stdlib + various fixes

This adds an opam package refinedrust-stdlib for the stdlib. Also, this fixes some things around the rr::context annotation, adds more later credits, and adds the static_has_refinement assertion to make timeless statements about refinements of statics.

case_studies/minivec/output/minivec/interface.rrlib

-{
-  "items": [
-    {
-      "kind": "adt",
-      "path": [
-        "Vec"
-      ],
-      "rtype": "Vec_inv_t_rt",
-      "semtype": "Vec_inv_t",
-      "syntype": "Vec_st"
-    },
-    {
-      "kind": "adt",
-      "path": [
-        "RawVec"
-      ],
-      "rtype": "RawVec_inv_t_rt",
-      "semtype": "RawVec_inv_t",
-      "syntype": "RawVec_st"
-    },
-    {
-      "kind": "method",
-      "name": "RawVec_T_ptr",
-      "path": [
-        "ptr"
-      ],
-      "spec": "type_of_RawVec_T_ptr"
-    },
-    {
-      "kind": "method",
-      "name": "RawVec_T_cap",
-      "path": [
-        "cap"
-      ],
-      "spec": "type_of_RawVec_T_cap"
-    },
-    {
-      "kind": "method",
-      "name": "RawVec_T_new",
-      "path": [
-        "new"
-      ],
-      "spec": "type_of_RawVec_T_new"
-    },
-    {
-      "kind": "method",
-      "name": "RawVec_T_grow",
-      "path": [
-        "grow"
-      ],
-      "spec": "type_of_RawVec_T_grow"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_len",
-      "path": [
-        "len"
-      ],
-      "spec": "type_of_Vec_T_len"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_new",
-      "path": [
-        "new"
-      ],
-      "spec": "type_of_Vec_T_new"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_push",
-      "path": [
-        "push"
-      ],
-      "spec": "type_of_Vec_T_push"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_pop",
-      "path": [
-        "pop"
-      ],
-      "spec": "type_of_Vec_T_pop"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_insert",
-      "path": [
-        "insert"
-      ],
-      "spec": "type_of_Vec_T_insert"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_remove",
-      "path": [
-        "remove"
-      ],
-      "spec": "type_of_Vec_T_remove"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_get_unchecked_mut",
-      "path": [
-        "get_unchecked_mut"
-      ],
-      "spec": "type_of_Vec_T_get_unchecked_mut"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_get_mut",
-      "path": [
-        "get_mut"
-      ],
-      "spec": "type_of_Vec_T_get_mut"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_get_unchecked",
-      "path": [
-        "get_unchecked"
-      ],
-      "spec": "type_of_Vec_T_get_unchecked"
-    },
-    {
-      "kind": "method",
-      "name": "Vec_T_get",
-      "path": [
-        "get"
-      ],
-      "spec": "type_of_Vec_T_get"
-    }
-  ],
-  "refinedrust_module": "generated_specs_minivec",
-  "refinedrust_name": "minivec",
-  "refinedrust_path": "refinedrust.examples.minivec.generated"
-}
\ No newline at end of file