[FEATURE] Add firmware update details

[Tom]

Is your feature request related to a problem? Please describe.
As requested by @frenck: Expose available data from Plugwise hardware through the module

Describe the solution you'd like
Add (eventually through integration) a binary sensor for firmware update

Additional context
Sifting through what the 'firmware status page' on a Anna looks like shown below, unfortunately mine is in 'auto-update' mode and as such 'locked' (can't change it), maybe because of its beta-status.

		<enabled>true</enabled>
		<firmware_locked>false</firmware_locked>
		<prevent_default_update>false</prevent_default_update>

[Bouwe Westerdijk]

Let's close this, it doesn't look like this is at all possible.