Add reolink documentation (#25306)

Co-authored-by: J. Nick Koston <nick@koston.org>

source/_integrations/reolink.markdown

@@ -0,0 +1,47 @@
+---
+title: Reolink NVR/camera
+description: Instructions on how to integrate Reolink devices (NVR/cameras) into Home Assistant.
+ha_category:
+  - Camera
+ha_iot_class: Local Polling
+ha_release: 2023.1
+ha_domain: reolink
+ha_codeowners:
+  - '@starkillerOG'
+ha_config_flow: true
+ha_platforms:
+  - Camera
+ha_integration_type: integration
+---
+
+The integration allows you to control [Reolink](https://reolink.com/) NVRs or cameras.
+
+{% include integrations/config_flow.md %}
+
+{% include integrations/option_flow.md %}
+{% configuration_basic %}
+Protocol:
+  description: Switch between RTSP or RTMP streaming protocol. 
+{% endconfiguration_basic %}
+
+## Camera streams
+
+This integration creates a few camera entities, one for each stream type with different resolutions: Main, Sub, Ext, and Images.
+The Sub stream camera entity is enabled by default; the other streams are disabled by default.
+The Images stream provides a sequence of image snapshots giving very low latency at the cost of a very low frame rate; this can be used when the hi-res RTMP/RTSP video stream has too much lag.
+
+## Tested models
+
+The following models have been tested and confirmed to work:
+
+- RLN8-410 NVR
+- RLC-811A
+- Reolink Video Doorbell PoE
+- Reolink Video Doorbell WiFi
+
+Battery-powered cameras are not yet supported.
+
+## Reolink firmware limitations
+
+- The Reolink NVR only sends event-notifications if motion happens on the camera connected to the first (index "0") channel, therefore the binary sensors of all channels will only be updated when the first channel sees motion.
+- Reolink doorbell presses only generate ONVIF event notifications when the doorbell is directly connected to your network. The doorbell visitor binary sensor will not work when connecting the Reolink doorbell to an NVR.