Refactor to better handle failures and reduce battery drain

[bdraco]

• There was no disconnect callback
• There was no overall timeout
• The cache was not cleared if a char was missing or service resolution failed (there are BleakError guards that may make this ineffective for some chars that might need to be removed, but I don't know which devices this is safe to do for)
• asyncio.wait_for creates a task and is not recommended for use because its changes cancellation semantics
• To reduce battery drain, once device info has been read, don't read it again except for the sw_version

Note the battery drain reduction change is only effective with this change in HA

diff --git a/homeassistant/components/airthings_ble/__init__.py b/homeassistant/components/airthings_ble/__init__.py
index 1d62442f14d..a26675cc310 100644
--- a/homeassistant/components/airthings_ble/__init__.py
+++ b/homeassistant/components/airthings_ble/__init__.py
@@ -40,11 +40,11 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
             f"Could not find Airthings device with address {address}"
         )

+    airthings = AirthingsBluetoothDeviceData(_LOGGER, elevation, is_metric)
+
     async def _async_update_method() -> AirthingsDevice:
         """Get data from Airthings BLE."""
         ble_device = bluetooth.async_ble_device_from_address(hass, address)
-        airthings = AirthingsBluetoothDeviceData(_LOGGER, elevation, is_metric)
-
         try:
             data = await airthings.update_device(ble_device)  # type: ignore[arg-type]
         except Exception as err:

[LaStrada]

2 linter errors, but other than that this PR seems to be working. I've tested this the last few days and I have had zero errors (except my previous comment).