Add configs to specify keepAlive and shutdownTimeout for GrpcQueryClient

[mayankshriv]

Added configs to specify keepAlive and shutdownTimeout for GrpcQueryClient.

• Added channelShutdownTimeoutSecond config for GrpcQueryClient with default of 10s.
• Added configs for keep-alive:
  • channelKeepAliveEnabled to enable/disable the feature, default false.
  • channelKeepAliveTimeSeconds to configures the interval for sending keep-alive pings, default 300 seconds (5 minutes).
  • channelKeepAliveTimeoutSeconds configures the timeout for waiting for a ping acknowledgment, default 300 seconds (5 minutes).
  • channelKeepAliveWithoutCalls ensures pings are sent even when there are no active calls, keeping the connection alive during idle period, default true.