Add Home Assistant integration documentation

[enoch85]

OVMS Home Assistant Documentation Overview

This documentation provides a comprehensive guide to integrating Open Vehicle Monitoring System (OVMS) with Home Assistant. It covers:

• Step-by-step instructions for setting up OVMS modules to communicate with Home Assistant using MQTT protocols, with accurate data usage expectations and performance metrics.
• Multiple implementation approaches, including the automated integration method (with HACS) and manual YAML configuration options to suit different user preferences.
• Detailed security implementation guidance for establishing secure TLS/SSL connections between OVMS, MQTT brokers, and Home Assistant.
• Practical optimization strategies to minimize data usage while maintaining functionality, with specific recommendations for both V2 and V3 protocols.
• Troubleshooting resources and configuration examples to help users resolve common integration challenges.

[enoch85]

@dexterbg I'm open for discussion on this one.

[enoch85]

Here's a good read about MQTT overhead: https://medium.com/@dheeptuck/how-to-optimize-data-usage-over-mqtt-792abebd2cd1

[enoch85]

cc @markwj as well. 👍