Reuse the locator connection

[Gsantomaggio]

• Reuse the locator connection. In this PR, the locator connection is always open ( like most other clients ) and can be reused. It is useful when API like storeOffset or queryOffest are often called. The maybeReconnectLocator function reconnects the locator if/when needed ( in case of network problem|)
• Remove one heartbeat Ticket.
• Fix an edge case during reconnection when the metadata fails
• closes Reuse the locator connection #387
• Fix a race condition for producer and consumer during the internal close. The internal close now has a cleanUp function