Add documentation for Aquacell integration (#32664)

* Added docs for AquaCell integration

* Update aquacell.markdown

* tiny tweaks

* Adjusted documentation according to changes in code

* Change signal level to signal strength

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

* Update source/_integrations/aquacell.markdown

---------

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

source/_integrations/aquacell.markdown

@@ -0,0 +1,37 @@
+---
+title: AquaCell
+description: Instructions on how to integrate AquaCell with Home Assistant.
+ha_category:
+  - Sensor
+ha_release: 2024.7
+ha_iot_class: Cloud Polling
+ha_config_flow: true
+ha_codeowners:
+  - '@Jordi1990'
+ha_domain: aquacell
+ha_platforms:
+  - sensor
+ha_integration_type: integration
+---
+
+AquaCell is a water-softening device. The **AquaCell** {% term integration %} allows you to monitor your AquaCell device in Home Assistant.
+You will need your Aquacell account information as used in the **AquaCell** app.
+
+{% include integrations/config_flow.md %}
+
+<div class='note warning'>
+This integration only works with <b>AquaCell</b> devices which have an <b>i-Lid</b> and are configured through the 'Mijn AquaCell' mobile app.
+</div>
+
+## Sensors
+
+This integration provides {% term sensors %} for the following information from the AquaCell device:
+
+- Percentage of salt remaining.
+- Time remaining until 0% salt level is reached.
+- iLid battery level.
+- Wi-Fi signal strength.
+
+<div class="note">
+The device does not update frequently, the integration polls the information once a day from the cloud.
+</div>