Major rework of Home Assistant MQTT config and additional info

[duhow]

• Use template functions to define components with custom content (sensor and switch)
• Better readability and easy of adding new components to Home Assistant
• Add entity_category to organize components into diagnostic (system info), config (switches) and default (image, camera and sensors).
• Add connections section to identify device via MAC address
• Reduce mqtt_adv_homeassistant.sh size about 10kb

[roleoroleo]

I'm not able to test this PR because I can't "destroy" my ha configuration.
My wife would not agree :)
If you've tested it I'll merge.

[duhow]

Sure, I have been testing this locally with my camera. This is the end result:

[duhow]

Depending on the status, the device has to be deleted from Home Assisstant MQTT and then reconfigured (keeps same identifiers) to repopulate all fields accordingly.

[roleoroleo]

Thank you for your code.

[roleoroleo]

@duhow
Do you agree if I copy your changes to the other projects (Allwinner and MStar)?

[duhow]

Sure @roleoroleo ! 👍🏻