Rework Entity Names in Discovery Template for HA >2023.8.0

[krkeegan]

Fixes the breaking change introduced in HomeAssistant 2023.8.0. The changes should not affect any existing user, and only alter the default friendly names generated for entities.

Proposed change

Generally removes the device_name as a prefix in entity name. For devices with only one entity, or for entities that provide the primary purpose of the device, the name is set to "" which causes HomeAssistant to use the device_name as the entity_name. For all other entities, HomeAssistant will automatically prepend the device_name to the entity_name.

Additional information

For a more detailed explanation on the HomeAssitant change see:
HomeAssistant Entity Naming Guidelines,
Change in MQTT Naming, and
Forum Discussion

• This PR fixes or closes issue: fixes HomeAssistant >2023.8.0 Warning: MQTT device name is equal to entity name in your config #514

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• Documentation added/updated

I already have this code running on my instance. I am waiting until later in August to merge into master as I will have more time then to deal with issues if they arise.