Add JS API to disable reloading in the current session

[adamchainz]

          Thanks for the idea, but I don't think this is the best approach. Injecting a floating button for this use case seems quite overbearing: the button can get in the way, extra CSS and JS are needed, and most users likely don't care.

If you have a few URLs that you don't want to reload, you can subclass the middleware to skip those. We could document how to do that.

Alternatively, we could add a JS API to disable reloading for the current browser session. Something like "open the dev console and type djangoBrowserReload.disable()". What do you think?

Originally posted by @adamchainz in #262 (comment)