Remove ensogl-pack

[mwu-tow]

Pull Request Description

This PR removes enso-pack (ensogl-pack) crate.
It still keeps the enso-runner JS package, as it is used for CLI argument parser and logger. The runner should be probably refactored (and possible removed altogether).

Important Notes

I've temporarily extracted the enso-runner to lib/js directory, as I wanted to avoid keeping pure JS library under lib/rust. Attempts at integrating this with app/ide-desktop and family caused too much trouble for this PR. The expectation is that the package will be removed or moved elsewhere soon anyway.

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed, the GUI was tested when built using ./run ide build.

[somebody1234]

approving ide-desktop changes, which consist solely of files being removed, and minor changes to package.json.