Add checks for whitespaces and executable scripts

[vxgmichel]

This PR adds the following builtin prek hooks to the pre-commit configuration and the CI code checker job:

• trailing-whitespace
• end-of-file-fixer
• check-shebang-scripts-are-executable
• check-executables-have-shebangs

It also fixes a couple of trailing spaces and executable scripts issues that have been detected by those hooks.

---

Context

I ran all the builtin prek hooks on the repository to see if any of them was failing. This is the full list:

- trailing-whitespace # Trim trailing whitespace
- check-added-large-files # Prevent committing large files
- check-case-conflict # Check for files that would conflict in case-insensitive filesystems
- check-illegal-windows-names # Check for filenames invalid on Windows
- end-of-file-fixer # Ensure newline at EOF
- file-contents-sorter # Sort lines in explicitly targeted files
- fix-byte-order-marker # Remove UTF-8 byte order marker
- check-json # Validate JSON files
- check-json5 # Validate JSON5 files
- pretty-format-json # Pretty format JSON files
- check-toml # Validate TOML files
- check-vcs-permalinks # Check that VCS links are permalinks
- check-yaml # Validate YAML files
- check-xml # Validate XML files
- mixed-line-ending # Normalize or check line endings
- check-symlinks # Check for broken symlinks
- destroyed-symlinks # Detect destroyed symlinks
- check-merge-conflict # Check for merge conflicts
- detect-private-key # Detect private keys
- no-commit-to-branch # Prevent committing to protected branches
- check-shebang-scripts-are-executable # Ensures that (non-binary) files with a shebang are executable
- check-executables-have-shebangs # Ensures that (non-binary) executables have a shebang

It turns out that 2 of them failed:

• trailing-whitespace
• check-executables-have-shebangs

Since this is evidence that those issues do occur, I suggest to integrate those checks, along with two similar hooks:

• end-of-file-fixer
• check-shebang-scripts-are-executable

Impact

Those hooks are fast (less than 100ms), and the extra CI job should not be costly either.

[vxgmichel]

Thanks @Millefeuille42 and @olivierh-pro for the review

However, #562 made it clear that we need a non-modifying version of the hooks we use so that they can be integrated in the Makefile.

The problem is that the trailing-whitespace and end-of-file-fixer hooks do not provide a non-modifying version.

I'm not sure how to deal with this, I'll have to bring the subject to the team. I switched the PR to draft in the meantime.