Enable beman-tidy default mode

[mariobullet]

issue: bemanproject/beman-tidy#259
Summary

• enable beman-tidy in default mode via pre-commit
• add the project LICENSE file and README license note
• rename sorted_list.pass.cpp to sorted_list.test.cpp and update the test target

[neatudarius]

This file should be discarded.

This repo already has a license file, but with WRONG naming - LICENSE.txt should be renamed to LICENSE (https://github.com/bemanproject/beman/blob/main/docs/beman_standard.md#toplevellicense).

More over, since we actually use APACHE license, please copy exact file from https://github.com/bemanproject/beman/blob/main/docs/beman_standard.md#licenseapache_llvm (a.k.a. https://github.com/bemanproject/beman/blob/main/LICENSE).

[neatudarius]

Please reimplement https://github.com/bemanproject/beman/blob/main/docs/beman_standard.md#readmelicense

Use exactly the following format:

## License

beman.exemplar is licensed under the Apache License v2.0 with LLVM Exceptions.

<!-- Other optional mentions go on this line ... >

TLDR: you should have sa single line beman.net is licensed under the Apache License v2.0 with LLVM Exceptions.

[neatudarius]

@mariobullet , discarded this PR as it seems more work to be done then starting from scratch - I will help you as indicated in bemanproject/beman-tidy#259 (comment).