topdown: Add units.parse builtin (#4676)

This function works on all base decimal and binary SI units of the set:

    m, K/Ki, M/Mi, G/Gi, T/Ti, P/Pi, and E/Ei

Note: Unlike `units.parse_bytes`, this function is case sensitive.

Fixes open-policy-agent#1802.

Signed-off-by: Philip Conrad <philipaconrad@gmail.com>

capabilities.json

@@ -3627,6 +3627,20 @@
         "type": "function"
       }
     },
+    {
+      "name": "units.parse",
+      "decl": {
+        "args": [
+          {
+            "type": "string"
+          }
+        ],
+        "result": {
+          "type": "number"
+        },
+        "type": "function"
+      }
+    },
     {
       "name": "units.parse_bytes",
       "decl": {