Add docs for new siren platform (#17128)

* Add docs for new siren platform

* Update docs based on core PR review and changes

* remove devices

* add info about input parameters

* Update source/_integrations/siren.markdown

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

* Update source/_integrations/siren.markdown

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

* Update source/_integrations/siren.markdown

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

* tweaks based on review

* additional feedback

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

source/_integrations/siren.markdown

@@ -0,0 +1,55 @@
+---
+title: Siren
+description: Instructions on how to set up siren devices within Home Assistant.
+ha_category:
+  - Siren
+ha_release: '2021.8'
+ha_domain: siren
+ha_quality_scale: internal
+ha_codeowners:
+  - '@home-assistant/core'
+  - '@raman325'
+ha_iot_class:
+---
+
+The Siren integration is built for the controlling and monitoring of siren/chime devices.
+
+Siren entities are created automatically by integrations that support them.
+
+## Services
+
+### siren services
+
+Available services: `siren.turn_on`, `siren.turn_off`, `siren.toggle`
+
+### Service `siren.turn_on`
+
+Turn the siren on.
+
+| Service data attribute | Optional | Description |
+| ---------------------- | -------- | ----------- |
+| `entity_id` | yes | String or list of strings that point at `entity_id`'s of sirens to control.
+
+There are three optional input parameters that can be passed into the service call depending on whether or not your device supports them. Check the device's integration documentation for more details.
+
+| Parameter Name  | Input Type
+|---------------- |-------------------------
+| `tone`          | `string` or `integer`
+| `duration`      | `integer`
+| `volume_level`  | `float` between 0 and 1
+
+### Service `siren.turn_off`
+
+Turn the siren off.
+
+| Service data attribute | Optional | Description |
+| ---------------------- | -------- | ----------- |
+| `entity_id` | yes | String or list of strings that point at `entity_id`'s of sirens to control.
+
+### Service `siren.toggle`
+
+Toggle the siren on/off.
+
+| Service data attribute | Optional | Description |
+| ---------------------- | -------- | ----------- |
+| `entity_id` | yes | String or list of strings that point at `entity_id`'s of sirens to control.