Add namespace-specific levels support to logger

[Nerivec]

Adds the ability to alter levels for specific namespaces.
Also:

• Bring "MQTT publish" lines back to info level and add z2m:mqtt namespace for whole MQTT class, to allow changing the level for that namespace specifically
• Replace warn for warning (with automatic remap if warn still used in config) to match syslog levels used
• Use settings for logger-related values throughout the code instead of repeating them
• Short-circuit winston if determined level won't end up logging anything (performance gain since all transport levels are synced, no need to go through that logic)
• Remove json option from File Transport, not supported (stale value?)

Example use:

advanced:
  log_namespaced_levels:
    z2m:mqtt: warning
    zh:ember:uart:ash: info

TODO

• frontend support for new setting (object with unknown string keys mapped to log level values)
• docs

[Nerivec]

@sjorge This, in combination with the debug-level regex should provide good customization for the logs. Let me know if you have any suggestions. With a bit of refactoring on the logger, and the fact this only looks up levels by key (namespace), it ends up way faster than the old calls in "filtered" scenario (noop), and about the same performance for "not filtered" scenario, so I think we're good on that end.
This setting should be more user-friendly, and the regex for debug more tailored for devs to filter out any which way they want.

[sjorge]

• Bring "MQTT publish" lines back to info level and add z2m:mqtt namespace for whole MQTT class, to allow changing the level for that namespace specifically

<3

This setting should be more user-friendly, and the regex for debug more tailored for devs to filter out any which way they want.

I started using this when that got implemented, it's working well for my needs. (I still have most info I care about and I can easily restart z2m when I need the info I filter out)

I'll try the other way when this gets added though, as I do indeed filter out 2 namespaces and nothing else.

Also I think your example in the PR comment is wrong? Looking at the diff should it not be:

advanced:
  log_namespaced_levels:
    'z2m:mqtt': warning
    'zh:ember:uart:ash': info

[Nerivec]

Good catch, forgot a step on the ladder!

The MQTT publish stuff is really dividing, between users who seem to use it all the time, and users who had gone to warn level to avoid the spamming it does in large network/fast-update devices (and can represent a massive amount of MQTT traffic). This should provide a way for both to be happy.

[Koenkk]

Created a PR for the docs. @Nerivec please check if all OK and move out of draft, then I can merge it.

[martyzeq]

looks promising, thank you guys !

[zen2]

As many, I miss MQTT messages in logs and it seems this new namespaces filtering can bring best of two world.

Anyway I wonder why we do not use "Notice" level because "Info" level should represent normal messages for current operations (like MQTT ones) and "Notice" only relevant ones. I mean that we could put back MQTT messages in "info" level and put actual "info" level in "notice". This way it is easy to choose which log level is needed quickly.

Note that advanced namespaces filtering is really a good stuff too and it can be complementary with a notice level especially to debug a particular topic. As it is filtering it should be use as advanced log configuration.

So to sum up, I propose this:

• move actual info level to a notice level
• move mqtt messages in info level
• keep namespaces filtering as advanced options