Add close endpoint to beekeeper
Add close endpoint so it will be possible to close wallet without restart of whole app
so whole procedure of interaction with beekeeper would look like this:
- open (open wallet file / mount hardware key)
- unlock (pass password so private keys are avaiable for signing)
- ... some operations ...
- lock (wallet still can be unlocked again and is visible, but private keys are secure)
- close (wallet file has been closed / hardware key has been unmounted, other app can access it now)
close can be called without lock, which is done implicitly, same as unlock an be called without open