…flip1995

Added `cargo dev setup git-hook` and updated `cargo dev setup intellij` including a `remove` command

This PR enables our dev tool to install a git hook that formats the code before each commit and also runs `update_lints` to make sure that everything is registered correctly. The script is located at `util/etc/pre-commit.sh`. I found it reasonable to locate it in the `util` folder and decided to add a `etc` in correlation to the main rust repo and to bring a bit of structure into it.

* The hook can be installed via: `cargo dev setup git-hook`
* And removed via: `cargo dev remove git-hook`

cc: rust-lang#5394

The refactoring of `src/ide_setup.rs` to `src/setup/intellij.rs` is an extra commit to simplify the review.

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Changes:
* Added `cargo dev setup git-hook` for formatting before every commit
* Added `cargo dev remove git-hook` to remove the hook again
* Added `cargo dev remove intellij` to remove rustc source path dependencies
* Changed `cargo dev ide_setup` to `cargo dev setup intellij`

changelog: none

This is only an internal change and therefore not worth an entry in the general change log.

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Tested on:
* [x] Linux (by `@xFrednet)`
* [ ] Windows (All used commands run inside the git bash, so it's very likely to work as well `@xFrednet)`
* [ ] macOS