[FLINK-37600] Add pre-commit git hook for common linting checks

[tomncooper]

What is the purpose of the change

There are several linting checks contained within the github actions pre-compile workflow.

It would be useful to have these checks run as a pre-commit hook in git so that any linting issues are spotted before they are pushed remotely.

This PR contains an example pre-commit git hook script in the new tools/git-hooks directory with instructions on how to symlink the script to the developers local .git/hooks directory.

This hook is entirely optional and once added can be skipped with the --no-verify flag.

Brief change log

• Add example pre-commit git hub script in the new tools/git-hooks directory.

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no

[flinkbot]

CI report:

• 8e5a974 Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[davidradl]

As per this weeks CHI meeting with @tomncooper, it would be good to decide what the server side implementation should be for checking pre commits, at the same time as proposing the client linting, so we can ensure that the checks are not duplicated and there is one golden version of checks.

The server side could drive the Git hooks using Git Actions.