adding timeout attribute to function node

- [x] New feature (non-breaking change which adds functionality)

Discussion here:
https://discourse.nodered.org/t/function-node-doesnt-have-timeout-feature/78483

## Proposed changes

Adding a timeout attribute to the function node, so an endless funciton doesnt break the node red server.

## Checklist

- [x] I have read the [contribution guidelines](https://github.com/node-red/node-red/blob/master/CONTRIBUTING.md)
- [x] For non-bugfix PRs, I have discussed this change on the forum/slack team.
- [x] I have run `grunt` to verify the unit tests pass
- [x] I have added suitable unit tests to cover the new/changed functionality

packages/node_modules/@node-red/nodes/locales/en-US/messages.json

@@ -248,7 +248,8 @@
             "initialize": "On Start",
             "finalize": "On Stop",
             "outputs": "Outputs",
-            "modules": "Modules"
+            "modules": "Modules",
+            "timeout": "Timeout (ms)"
         },
         "text": {
             "initialize": "// Code added here will be run once\n// whenever the node is started.\n",