edge-patron is leaking HttpClient Objects

We do not close the HttpClient created in the OkapiClient. We could either cache the per tenant OkapiClient created by the PatronOkapiClientFactory so that only one client is created per tenant or we could close the PatronOkapiClient in the PatronHandler.handleCommon().

Since keepAlive is set to false in OkapiClient, connection pooling will not be used anyway, so closing the connection in handleCommon is probably the simplest, but least performant, fix.