gh-actions: introduce bazel cache

[TimotheusBachinger]

Thank you for your interest in contributing to Checkmk!
Consider looking into Readme regarding process details.

General information

Please give a brief summary of the affected device, software or appliance.
Keep in mind that we are experts in monitoring, but we cannot be experts on all supported devices.
A little context will help us assess your proposed change.

Bug reports

Please include:

• Your operating system name and version
• Any details about your local setup that might be helpful in troubleshooting
• Detailed steps to reproduce the bug
• An agent output or SNMP walk
• The ID of a submitted crash report for reference (if applicable)

Proposed changes

Sometimes it is hard for us to assess the quality of a fix.
While it may work for you, it is our job to ensure that it works for everybody.
These are some ways to help us:

• What is the expected behavior?
• What is the observed behavior?
• If it's not obvious from the above: In what way does your patch change the current behavior?
• Consider writing a unit test that would have failed without your fix.
• Is this a new problem? What made you submit this PR (new firmware, new device, changed device behavior)?

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[TimotheusBachinger]

I have read the CLA Document and I hereby sign the CLA or my organization already has a signed CLA.