Add a web editor to edit locustfile.py

[mosesliao]

Prerequisites

• I am using the latest version of Locust
• I am suggesting a new feature, not asking a question

Description

I would like a web file editor on locust app to edit locustfile.py In doing so it helps users to edit the python file and run the load test again on the cluster without the need to change it on local machine and upload it again to a remote cloud and run the load test. this help save the upload time.

[cyberw]

I don't think we'll want to introduce the overhead of a full editor, but what are planning on doing is to make support for reloading the locustfile without restarting all of locust. Then locust could watch the file and reload it on any changes.