Removes a bulk of rust crates that we no longer need, but that added significant install, build and testing time to the Rust parser.
Most significantly, removed `enso-web` and `enso-shapely`, and got rid of many no longer necessary `#![feature]`s. Moved two still used proc-macros from shapely to prelude. The last remaining usage of `web-sys` is within the logger (`console.log`), but we may actually want to keep that one.
This PR updates the Rust toolchain to recent nightly.
Most of the changes are related to fixing newly added warnings and adjusting the feature flags. Also the formatter changed its behavior slightly, causing some whitespace changes.
Other points:
* Changed debug level of the `buildscript` profile to `lint-tables-only` — this should improve the build times and space usage somewhat.
* Moved lint configuration to the worksppace `Cargo.toml` definition. Adjusted the formatter appropriately.
* Removed auto-generated IntelliJ run configurations, as they are not useful anymore.
* Added a few trivial stdlib nightly functions that were removed to our codebase.
* Bumped many dependencies but still not all:
* `clap` bump encountered https://github.com/clap-rs/clap/issues/5407 — for now the warnings were silenced by the lint config.
* `octocrab` — our forked diverged to far with the original, needs more refactoring.
* `derivative` — is unmaintained and has no updated version, despite introducing warnings in the generated code. There is no direct replacement.
