Add clang-tidy reviews to CI

[slaren]

Adds clang-tidy static analyzer and linter checks to pull requests.

The failed checks are reported in the PR in a comment, see these for some examples:
slaren#11
slaren#12 (here it finds a bug in the command line parsing of benchmark-matmult.cpp)

I tried to remove some of the most pedantic checks, but there are still a lot of failed checks in the current code that should be addressed over time. However, the workflow action will only report the checks failed in the lines modified by the PR, so the current issues will not be blamed on new PRs (unless they happen to be in the lines modified by the PR).

To test the settings in .clang-tidy locally:

• Configure cmake with -DCMAKE_EXPORT_COMPILE_COMMANDS=on
• Run clang-tidy with the cmake build path in -p and the source file, for example:
  clang-tidy -p build llama.cpp

Note that since this adds comments to the PRs, it requires adding write permissions to the workflows in the project settings.

[ggerganov]

Should already have the write permission:

[Green-Sky]

I wanted to ask if it uses clang-tidy-diff, but the change suggestions look fine too.

[slaren]

It doesn't use clang-tidy-diff, but essentially it does the same, it checks what lines were modified and passes a -line-filter argument to clang-tidy. This is the action that I am using: https://github.com/marketplace/actions/clang-tidy-review