Add Kmtronic (#15953)

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

source/_integrations/kmtronic.markdown

@@ -0,0 +1,16 @@
+---
+title: KMTronic
+description: Integrate KMTronic devices
+ha_category:
+  - Switch
+ha_release: 2021.3 
+ha_codeowners:
+  - '@dgomes'
+ha_iot_class: Local Push
+ha_domain: kmtronic
+ha_config_flow: true
+---
+
+Integrate [KMtronic devices](https://www.kmtronic.com/) into Home Assistant. KMtronic offers a large range of IP-connected relays that can be controlled over your local area network. This integration maps each of the relays as a separate device, enabling you to control various areas of your home (e.g. using each relay to control different garden sprinkler areas, or controlling the electrical distribution of your house from a central board).
+
+{% include integrations/config_flow.md %}