Add docs for Sanix integration (#30587)

* Add docs for Sanix integration

* Apply suggestions from code review

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

* Add docs for Sanix integration

* Add docs for Sanix integration

* Add docs for Sanix integration

* Apply suggestions from code review

Co-authored-by: c0ffeeca7 <38767475+c0ffeeca7@users.noreply.github.com>

---------

Co-authored-by: Franck Nijhof <frenck@frenck.nl>
Co-authored-by: c0ffeeca7 <38767475+c0ffeeca7@users.noreply.github.com>

source/_integrations/sanix.markdown

@@ -0,0 +1,31 @@
+---
+title: Sanix
+description: Instructions on how to integrate Sanix devices within Home Assistant.
+ha_category:
+  - Switch
+ha_release: 2024.5
+ha_iot_class: Cloud Polling
+ha_config_flow: true
+ha_codeowners:
+  - '@tomaszsluszniak'
+ha_domain: sanix
+ha_platforms:
+  - sensor
+ha_integration_type: integration
+---
+
+The Sanix {% term integration %} allows you to get water/sewage level sensor measurements from the Sanix devices made by [BIT Complex](https://bitcomplex.pl/).
+
+## Pre-requisites
+
+To set up the {% term integration %}, go to the [Sanix dashboard](https://sanix.bitcomplex.pl) and sign in to your account.
+
+Not anyone can pull your data from the API. You need to authenticate by using an API token. To retrieve your API token, on the [Sanix dashboard](https://sanix.bitcomplex.pl), go to the **Help** page, and under **System version**, copy your API token. You will need this during setup in Home Assistant.
+
+## Configuration
+
+[![Open your Home Assistant instance and start setting up a new integration.](https://my.home-assistant.io/badges/config_flow_start.svg)](https://my.home-assistant.io/redirect/config_flow_start/?domain=sanix)
+
+## Hardware support
+
+- Sanix S M25 (<b>3.10</b> firmware version).