add bsblan documentation (#12241)

Co-Authored-By: Klaas Schoute <klaas_schoute@hotmail.com>
Co-Authored-By: Franck Nijhof <frenck@frenck.nl>

source/_integrations/bsblan.markdown

@@ -0,0 +1,43 @@
+---
+title: BSBLan
+description: Instructions on how to integrate BSBLan device into Home Assistant.
+logo: bsblan.png
+ha_category: Climate
+ha_release: 0.110
+ha_iot_class: Local Polling
+ha_config_flow: true
+ha_codeowners:
+  - "@liudger"
+---
+
+This integration integrates [BSBLan](https://github.com/fredlcore/bsb_lan) device into Home Assistant.
+
+BSBLan is a device that is made by `Frederik Holst` and `Ulf Diekmann` for documentation and with
+the help of many other contributors.
+The board is designed for an Arduino Mega 2560 with an Ethernet-Shield for web-based controlling
+of heating systems such as `Elco Thision`, `Brötje` and similar systems.
+
+It can interface with the heating system over Boiler-System-Bus, Local Process Bus and PPS (Punkt-zu-Punkt Schnittstelle)
+For more information of which system it supports, have a look at their [documentation](https://1coderookie.github.io/BSB-LPB-LAN_EN/).
+
+## Configuration
+
+This integration can be configured using the integrations in the
+Home Assistant frontend.
+
+Menu: **Configuration** -> **Integrations**.
+
+Click on the `+` sign to add an integration and click on **BSBLan**.
+Fill in the IP address of the device in your network and, if needed,
+the port number. The default value should be 80.
+For authentication now only passkey is supported.
+Username and password are not supported yet. This will be supported in the next release.
+
+After completing the configuration flow, the BSBLan Climate integration will be
+available.
+
+For more documentation of the BSBLan device, check the [manual](https://1coderookie.github.io/BSB-LPB-LAN_EN/).
+The device support quite a few controllers from different manufacturers.
+[list of supported models](https://1coderookie.github.io/BSB-LPB-LAN_EN/chap03.html#313-other-manufacturers)
+
+The integration is tested with firmware latest stable version `v0.43`.