Add function to list all the key-values in the boltdb store

[richardpen]

As today the boltdb store provides a function to List the key value pairs by prefix, but it doesn't accept any regular expression. Also, the prefix can't be empty, which means I can't get all the key-value pairs without knowing the prefix for all the keys. I think it would be reasonable to provide a way to retrieve all the key-value pairs by accepting an empty prefix. Any thoughts on this?

[Bobsar0]

I second this. Any response update so far? @richardpen