Adding RustRover support for JetBrains

[msedgren]

I'd like to modify the jetbrains support to add RustRover as a supported option. This is a bit complex as the original plugin (I think) may not be getting updated anymore. On top of that, there are cursorless type plugins that, I believe, rewrote this functionality and are built on top of it (at least the one I did called cursing_less does). So, adding it in one spot would require adding the same support in multiple plugins, but that's probably better than not working at all. For now, I am just modifying my local copies.

[nriley]

From the community backlog session — most of us were not aware that discussions even existed and were not monitoring them. This seems like a reasonable idea; you might want to bring it up in the JetBrains channel on Slack.