Add storage helper to ZHA and use it for the device node descriptor

[dmulcahey]

This PR adds storage to ZHA and leverages it for storing the zigbee node descriptor so that we have the device specific power profile and the manufacturer code available for us to use. Eventually it will house the group id's and tables for multicast transmissions (real zigbee light groups) and the neighbor and rousing tables that we can use for network visualization among other things.

@balloob looking for your feedback on the storage usage if you don't mind... want to make sure I did this correctly.

[balloob]

looks fine

[dmulcahey]

@balloob are we good when the build passes?

[ckpt-martin]

Hi @dmulcahey,
Since the addition of the storage helper my ZigBee USB stick no longer works with ZHA. It works fine up to 0.89.2. But as soon as I upgrade to any 0.9x release Zigbee stops working with an error related to store.py. It looks like it is having an issue accessing or storing the power_source and manufacturer code of my stick.
I use the Bitronvideo AV2010/10 (http://bvsite.smabit.eu/index.php/produkte/smart-home-produkte/zb-funkstick/ - site is in German bit the specs are there).
This is the error that HA throws when starting:

2019-06-25 15:54:38 INFO (MainThread) [homeassistant.setup] Setting up zha
2019-06-25 15:54:38 INFO (MainThread) [homeassistant.setup] Setup of domain zha took 0.0 seconds.
2019-06-25 15:54:38 ERROR (MainThread) [homeassistant.config_entries] Error setting up entry /dev/ttyUSB0 for zha
Traceback (most recent call last):
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/config_entries.py", line 302, in async_setup
    result = await component.async_setup_entry(hass, self)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/zha/__init__.py", line 150, in async_setup_entry
    zha_storage = await async_get_registry(hass)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/zha/core/store.py", line 160, in async_get_registry
    return cast(ZhaDeviceStorage, await task)
  File "/usr/lib/python3.5/asyncio/futures.py", line 380, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.5/asyncio/tasks.py", line 304, in _wakeup
    future.result()
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/asyncio/tasks.py", line 239, in _step
    result = coro.send(None)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/zha/core/store.py", line 155, in _load_reg
    await registry.async_load()
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/zha/core/store.py", line 112, in async_load
    power_source=device['power_source'],
KeyError: 'power_source'

I have went back to HA 0.89.2 where everything works. But I would like to upgrade HA at some point. Would be nice we could fix this. Thanks.

[MartinHjelmare]

Please open an issue if you suspect a bug.

If you want to suggest an enhancement please open a feature request in the Feature Requests section of our community forum.

Merged PRs should not be used for enhancement discussion or bug reports. If you've found a bug it's ok to make a review with inline comments and link to an issue that reports the bug.

Thanks!