Don't have the Rust runtime as the default for `bend run`

[developedby]

Is your feature request related to a problem? Please describe.
The Rust runtime is the reference implementation, but it's slow and doesn't have IO.
It's confusing for new users.

Describe the solution you'd like
Change bend run command into bend run-rs.

Describe alternatives you've considered

• Also making run default to run-c.

[bhavik-goplani]

@developedby I'd like to work on this issue. Is there anything I should know before working on this?

[developedby]

You need to update the cli tests to the new command. in tests/golden_tests/cli/*

To run the tests you need to install cargo-insta cargo install cargo-insta, run them with cargo insta test and then update the snapshots with cargo insta review if anything changed.

[imaqtkatt]

fixed #630