Breaking up envvars and config settings into separate settings pages (#1028)

- Creates a slew of folders and pages nested under the mc-server page to store settings.
- Breaks up all of the environment variable options formerly in the mc-server page into these separate pages.
- Moves the config settings formerly in the mc admin config page to the appropriate new settings pages.
- Adds a MiniO Client settings page and document `mc-host-<alias>`

Closes #1017

source/reference/minio-server/settings/notifications.rst

@@ -0,0 +1,74 @@
+.. _minio-server-envvar-notifications:
+.. _minio-server-config-logging-logs:
+
+=============================
+Bucket Notifications Settings
+=============================
+
+.. default-domain:: minio
+
+.. contents:: Table of Contents
+   :local:
+   :depth: 2
+
+This page covers settings that control behavior related to :ref:`MinIO bucket notifications <minio-bucket-notifications>`. 
+
+.. include:: /includes/common-mc-admin-config.rst
+   :start-after: start-minio-settings-defined
+   :end-before: end-minio-settings-defined
+
+Sync Events
+-----------
+
+*Optional*
+
+.. tab-set::
+
+   .. tab-item:: Environment Variable
+      :sync: envvar
+
+      .. envvar:: MINIO_API_SYNC_EVENTS
+
+   .. tab-item:: Configuration Setting
+      :sync: config
+
+      .. mc-conf:: sync_events         
+
+.. include:: /includes/common-mc-admin-config.rst
+   :start-after: start-minio-api-sync-events
+   :end-before: end-minio-api-sync-events
+
+Supported Notification Targets
+------------------------------
+
+Notifications require a target to receive the events.
+MinIO supports a variety of possible targets.
+Settings for each target type have their own pages.
+Select the appropriate link below for the type of target you use for notifications.
+
+- :ref:`minio-server-envvar-bucket-notification-amqp`
+- :ref:`minio-server-envvar-bucket-notification-elasticsearch`
+- :ref:`minio-server-envvar-bucket-notification-kafka`
+- :ref:`minio-server-envvar-bucket-notification-mqtt`
+- :ref:`minio-server-envvar-bucket-notification-mysql`
+- :ref:`minio-server-envvar-bucket-notification-nats`
+- :ref:`minio-server-envvar-bucket-notification-nsq`
+- :ref:`minio-server-envvar-bucket-notification-postgresql`
+- :ref:`minio-server-envvar-bucket-notification-redis`
+- :ref:`minio-server-envvar-bucket-notification-webhook`
+
+.. toctree::
+   :titlesonly:
+   :hidden:
+   
+   /reference/minio-server/settings/notifications/amqp
+   /reference/minio-server/settings/notifications/elasticsearch
+   /reference/minio-server/settings/notifications/kafka
+   /reference/minio-server/settings/notifications/mqtt
+   /reference/minio-server/settings/notifications/mysql
+   /reference/minio-server/settings/notifications/nats
+   /reference/minio-server/settings/notifications/nsq
+   /reference/minio-server/settings/notifications/postgresql
+   /reference/minio-server/settings/notifications/redis
+   /reference/minio-server/settings/notifications/webhook-service
+