Update logging messages in the VM

[Fumuran]

This small PR updates the formatting of the logging messages in the VM to be in the same style with logging messages from Winterfell.

[Fumuran]

I'm wondering should we add a new command to make to make enabling tracing-forest feature more convenient? Make it similar to the FEATURES_CONCURRENT_EXEC, but with tracing-forest feature. Something like:

FEATURES_LOG_TREE=--features concurrent,executable,tracing-forest

exec-tree:
    cargo build $(PROFILE_OPTIMIZED) $(FEATURES_LOG_TREE)

[bobbinth]

I'm wondering should we add a new command to make to make enabling tracing-forest feature more convenient? Make it similar to the FEATURES_CONCURRENT_EXEC, but with tracing-forest feature. Something like:

Good idea! I'd probably call it exec-info. Also, would we not need to set log level to INFO for it to work?

[Fumuran]

Also, would we not need to set log level to INFO for it to work?

No, there is no need to change the default log level, we specify it on the execution stage, so the only thing we need to change is a Makefile