Catch and handle gRPC status and logs

[leodido]

What would you like to be added:

Our gRPC server should be able to listen for gRPC runtime statuses and react to them accordingly.

Also the Falco's gRPC server should catch the gRPC logs.

Why is this needed:

The gRPC C++ implementation does not uses exception as per Google C++ coding guide. Thus we do not have exceptions to detect misbehaviours. We need to observer the gRPC internal status and react to it.

For example when input certificates for mutual TLS are wrong (eg., empty files) it segfaults and we are not able to correcly handle it.

Similarly we would like to catch the gRPC C++ implementation logs in order to filter and/or expose them with our logger and our logging format.

Refs #822

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[fntlnz]

Stalebot we need to keep this !!

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[fntlnz]

Oh no please keep!

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[leodido]

In https://github.com/falcosecurity/falco/pull/1241/files we have setup the dispatching of gRPC engine logs to falco_logger.

This should be sufficient for now.