[clientlib-ktx] Local auth/reauth should occur automatically

[creativedrewy]

Currently consumers of clientlib-ktx have to manually authorize/reauthorize the connection every time they transact. This can lead to unfortunate bugs with mismatched auth tokens & wallets.

The transact method should take an option auth token as an argument, the assumption being that if no auth token is passed in, an authorization operation is performed. If a token is passed in, a reauthorization is asssumed.