Add beyla integration test

[wildum]

I reworked the integration tests to use test containers instead of running Alloy's binary on the host directly for two reasons:

• some components (such as the Beyla one) require rights that the Github runner's host does not have. This is solved by running Alloy in test containers with privileges.
• some components only run on specific linux (for example Beyla, Unix, SNMP). Now that Alloy is running in a test container, the tests don't depend on the OS anymore

Additionally I added a test for Beyla

The annoying bit is that building the Alloy docker image takes time and disk space. As a result, I needed to use a bigger github runner for this task

[ptodev]

The annoying bit is that building the Alloy docker image takes time and disk space. As a result, I needed to use a bigger github runner for this task

Can the integration tests reuse the docker image which the "official" CI step for image generation created?

[ptodev]

It'd be nice to put this in the main require block.