[Embedded node] Option to extract channel.db

[Darth-Coin]

Describe your enhancement idea

We've seen some Zeus embedded users messing up opening / closing channels and end up with zombie channels.
For this situation, the user do not have another option than extract the channel.db file from his mobile device and proceed with ChanTools on a PC.

But for many users this procedure is not well known or is not even possible in easy way.

I suggest to add a special feature, for this disaster situation, where the user can copy the channel.db file onto his local mSD card or "Download" folder on his local storage, easily accessible later with a PC.

Please also put an alert that the file could be quite big sometimes, depending on their previous activity.