Document logging configuration (#3397)

* Document logging configuration
* Document default log_nonblock values for different loggers

Resolves #1974
Resolves #2242

doc/reference/configuration/cfg_feedback.rst

@@ -0,0 +1,49 @@
+.. _cfg_feedback:
+
+* :ref:`feedback_enabled <cfg_logging-feedback_enabled>`
+* :ref:`feedback_host <cfg_logging-feedback_host>`
+* :ref:`feedback_interval <cfg_logging-feedback_interval>`
+
+By default, a Tarantool daemon sends a small packet
+once per hour, to ``https://feedback.tarantool.io``.
+The packet contains three values from :ref:`box.info <box_introspection-box_info>`:
+``box.info.version``, ``box.info.uuid``, and ``box.info.cluster_uuid``.
+By changing the feedback configuration parameters, users can
+adjust or turn off this feature.
+
+.. _cfg_logging-feedback_enabled:
+
+.. confval:: feedback_enabled
+
+    Since version 1.10.1. Whether to send feedback.
+
+    If this is set to ``true``, feedback will be sent as described above.
+    If this is set to ``false``, no feedback will be sent.
+
+    | Type: boolean
+    | Default: true
+    | Environment variable: TT_FEEDBACK_ENABLED
+    | Dynamic: **yes**
+
+.. _cfg_logging-feedback_host:
+
+.. confval:: feedback_host
+
+    Since version 1.10.1. The address to which the packet is sent.
+    Usually the recipient is Tarantool, but it can be any URL.
+
+    | Type: string
+    | Default: ``https://feedback.tarantool.io``
+    | Environment variable: TT_FEEDBACK_HOST
+    | Dynamic: **yes**
+
+.. _cfg_logging-feedback_interval:
+
+.. confval:: feedback_interval
+
+    Since version 1.10.1. The number of seconds between sendings, usually 3600 (1 hour).
+
+    | Type: float
+    | Default: 3600
+    | Environment variable: TT_FEEDBACK_INTERVAL
+    | Dynamic: **yes**