[suggestion] Simplify logger's behaviour and configuration

[0x009922]

Description

I think the current logger's behaviour & configuration are a little overcomplicated, and I see a way to make its UX more straightforward and useful.

Current implementation

Iroha prints logs into standard output in default way and optionally into a file in JSON format.

There are these options:

• level: logging verbosity
• compact_mode: flag to make logs in the standard output less verbose in terms of format
• terminal_colors: flag to control ANSI colouring in the standard output
• log_file_path: enables JSON logging into a file, in a addition to standard output

log_file_path seems not useful for me here. It is the only way to get JSON logs, and if you need JSON logs, than you most probably don't need any other logs. However, stdout is always busy with default logging.

Apart from that, I've created a separate issue for removal of terminal_colors from the logger configuration:

• [suggestion] Move logger.terminal_colors setting to the CLI layer #4030

Proposal

• Remove terminal_colors ([suggestion] Move logger.terminal_colors setting to the CLI layer #4030), log_file_path and compact_mode
• Use stdout and a single output destination. It is easy to redirect it wherever, e.g. into a file.
• Introduce format option to change the format of logger output. I think we can just adopt the formats supported by tracing_subscriber out of the box:
  • full: default format now
  • compact: what is now enabled with compact_mode
  • pretty: I would personally very appreciate having this option, it might be very helpful during debugging of Iroha and development of SDK
  • json: JSON machine-readable output

So, after all there will be only two options to configure: level and format.

[0x009922]

Closed by #4100