Fix memory churn in state templates (#90685)

* Fix memory churn in state templates

The LRU for state templates was limited to 512 states. As soon
as it was exaused, system performance would tank as each template
that iterated all states would have to create and GC any state
> 512

* does it scale?

* avoid copy on all

* comment

* preen

* cover

* cover

* comments

* comments

* comments

* preen

* preen

homeassistant/bootstrap.py

@@ -239,6 +239,7 @@ async def load_registries(hass: core.HomeAssistant) -> None:
 
     # Load the registries and cache the result of platform.uname().processor
     entity.async_setup(hass)
+    template.async_setup(hass)
     await asyncio.gather(
         area_registry.async_load(hass),
         device_registry.async_load(hass),