Logdir fixes

[richcarl]

Ensures that log files and directories are not created when running in foreground mode.
Closes #3860

[dincho]

Couple of issues as we already discussed:

• foreground doesn't handle CRTL+C which is a must in interactive usage and for orchestrators
• the default log level should be INFO instead of DEBUG as it was for console output

[richcarl]

Turns out that Erlang actually handles SIGTERM these days as equivalent to running init:stop(), so plain docker stop will do a clean shutdown. Good to know.

@dincho Do you have some reference you can point me to that states clearly what is expected with regard to SIGINT in Docker?

[dincho]

I don't think that this is docker specific, this is general UNIX/POSIX process expectations. When you hit CRTL+C you expect the process to stop "immediately" or you (at least me) never run that crap again.

[dincho]

Turns out that Erlang actually handles SIGTERM these days as equivalent to running init:stop(), so plain docker stop will do a clean shutdown. Good to know.

I guess the process doesn't stop on time then and get's killed: https://docs.docker.com/reference/cli/docker/container/stop/#description