introduce new builtin crypto.parse_private_keys

* crypto.parse_private_keys parses private keys, returns a list of valid
keys
* consolidated getPrivateKeysFromString  with getPrivateKeysFromPEMData
for crypto.x509.parse_rsa_private_key  and crypto.parse_private_keys

* reworked crypto.x509.parse_rsa_private_key so that we no longer need
getPrivateKeysFromString  but instead determine type of key in builtin
function and added input validation checks

Co-authored-by: Charlie Egan <git@charlieegan3.com>
Signed-off-by: Emil Volckmar Ry <emilvry@gmail.com>

capabilities.json

@@ -671,6 +671,31 @@
         "type": "function"
       }
     },
+    {
+      "name": "crypto.parse_private_keys",
+      "decl": {
+        "args": [
+          {
+            "type": "string"
+          }
+        ],
+        "result": {
+          "dynamic": {
+            "dynamic": {
+              "key": {
+                "type": "string"
+              },
+              "value": {
+                "type": "any"
+              }
+            },
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "type": "function"
+      }
+    },
     {
       "name": "crypto.sha1",
       "decl": {