Replace :: logger context separator with more commonly used .

[azasypkin]

To make this work we should change config parsing code a bit since . in property names is used for nested config objects currently, but it should be doable.

[azasypkin]

Hey @kjbekkelund, could you please explain a little bit more what you meant here? Do you want to expand only "top-level" properties or what?

Hm, wonder if we could use . as separator if we reworked the logic here https://github.com/elastic/kibana/blob/new-platform/platform/config/__tests__/ensureDeepObject.test.ts#L51-L69 to something like:

test("don't expand nested properties", () => {
  const obj = {
    'foo.bar': {
      'quux.a': 1,
      b: 2
    }
  };

  expect(ensureDeepObject(obj)).toEqual({
    foo: {
      bar: {
        'quux.a': 1,
        b: 2
      }
    }
  });
});

Another idea is that we can go back to the initial approach and use array for loggers, that would probably simpler, but a bit more confusing though as context field is supposed to be unique :/

logging:
  appenders:
    console:
      kind: console
      layout:
        kind: pattern
        highlight: true

  root:
    level: all
    appenders: [console]

  loggers:
    - context: plugins.pid
      level: info
      appenders: [file]
    - context: server
      level: warn

[azasypkin]

I see that log4j 2 uses array for loggers if yaml config is used: https://dzone.com/articles/log4j-2-configuration

[azasypkin]

@kjbekkelund would you mind giving me a brief feedback on e6e6dcd?

[azasypkin]

Fixed via 052982d