Kernel log output should also be sent to slog

[mhofman]

What is the Problem Being Solved?

The slog capture detailed structured log events of SwingSet activity. One of these event is of type console, and can have source liveslots or vat. These console output are also sent to the stdout/stderr of the kernel process. The kernel also generate console output of its own, but does not generate console slog events for these, making it hard to use the slog as a single source of information.

Description of the Design

Update the logger endowed to the kernel to also send log calls to the slog sender with {type: 'console', source: 'kernel'}.

Security Considerations

None

Scaling Considerations

None

Test Plan

Manually verify that slog events contain kernel console output.

Upgrade Considerations

Chain software but does not affect consensus.