Add cmake-format

[nkoukpaizan]

Description

This add cmake-format hooks to harmonize CMake files.

I noticed the need for manual formatting in #394. I thought we had added this at the same time as Re::Solve, but it must have slipped through the cracks.

Proposed changes

• Added .cmake-format.py. I tried to match the existing style as much as possible.
• Added cmake-format hook to .pre-commit-config.yaml.
• CI should modify CMake files accordingly.

Checklist

• All tests pass.
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• [N/A] The new code follows GridKit™ style guidelines.
• [N/A] There are unit tests for the new code.
• [n/A] The new code is documented.
• The feature branch is rebased with respect to the target branch.
• I have updated CHANGELOG.md to reflect the changes in this PR. If this is a minor PR that is part of a larger fix already included in the file, state so.

Further comments

Formatting-only changes.