Capacity to iterate the found keys

[SR-G]

Except if i missed it, at least at "LocalConfig" level, it's not possible to retrieve all keys and to iterate over them.
There is a "GetAll", but only about returning all values attached to one key.
A "GetAllKeys()" would be useful.

[dominikschulz]

We might be missing that, indeed.

I see how GetAllKeys would be useful and should consider adding it.