multi: add zero-conf, scid-alias channel-types to rpc

This allows the open channel rpcs to use the zero-conf or scid-alias
channel types.

lnrpc/lightning.swagger.json

@@ -5418,6 +5418,14 @@
         "commitment_type": {
           "$ref": "#/definitions/lnrpcCommitmentType",
           "description": "The explicit commitment type to use. Note this field will only be used if\nthe remote peer supports explicit channel negotiation."
+        },
+        "zero_conf": {
+          "type": "boolean",
+          "description": "If this is true, then a zero-conf channel open will be attempted."
+        },
+        "scid_alias": {
+          "type": "boolean",
+          "description": "If this is true, then an option-scid-alias channel-type open will be\nattempted."
         }
       }
     },