Add sighthound docs (#11203)

* Add sighthound docs

* Address reviewer comments

* Bump ha_release

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

source/_integrations/sighthound.markdown

@@ -0,0 +1,52 @@
+---
+title: "Sighthound"
+description: "Detect people with Sighthound Cloud."
+logo: sighthound-logo.png
+ha_category:
+  - Image Processing
+ha_release: 0.105
+ha_iot_class: Cloud Polling
+---
+
+Adds integration for person detection with [Sighthound Cloud](https://www.sighthound.com/products/cloud). The Sighthound Developer tier (free for non-commercial use) allows 5000 requests per month. If you need more requests per month you will need to sign up for a production account (i.e., Basic or Pro account).
+
+This integration adds an image processing entity where the state of the entity is the number of people detected in an image. For each person detected, an `image_processing.person_detected` event is fired. The event data includes the entity_id of the image processing entity firing the event, and the bounding box around the detected person. 
+
+**Note** that in order to prevent accidentally using up your requets to Sighthound, by default the component will not automatically scan images, but requires you to call the `image_processing.scan` service e.g. using an automation triggered by motion. Alternativley, periodic scanning can be enabled by configuring a `scan_interval`.
+
+## Configuration
+
+To enable this platform in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+image_processing:
+  - platform: sighthound
+    api_key: some_key
+    source:
+      - entity_id: camera.my_cam
+```
+
+{% configuration %}
+api_key:
+  description: Your Sighthound Cloud API key.
+  required: true
+  type: string
+account_type:
+  description: If you have a paid account, used `prod`.
+  required: false
+  type: string
+source:
+  description: The list of image sources.
+  required: true
+  type: map
+  keys:
+    entity_id:
+      description: A camera entity id to get a picture from.
+      required: true
+      type: string
+    name:
+      description: This parameter allows you to override the name of your `image_processing` entity.
+      required: false
+      type: string
+{% endconfiguration %}