Fix PCT-879: API gatekeeper collides with agent keepalive (pong). Use time.Ticker instead of time.Timer. Keepalive is no longer dynamic.
Fix PCT-879: API gatekeeper collides with agent keepalive (pong). Use time.Ticker instead of time.Timer. Keepalive is no longer dynamic.

vadimtk/metrics-agent,vadimtk/metrics-agent