[Access] Implement keepalive routine with ping-ponging to ws connection in ws controller

[Guitarheroua]

Develop a separate Keepalive module for the web socket controller to monitor network availability using WebSocket ping-pong service messages.

Requirements:

• The Keepalive module should be instantiated and managed by the web socket controller but function independently.
• The module should operate autonomously to detect connectivity issues.
• If issues are detected, it should:
  • Disable the WebSocket connection.
  • Trigger a graceful shutdown of the affected parts of the web socket controller.
• The logic for this functionality can be derived from the proof of concept (PoC) implementation in Flow-Go:
  https://github.com/onflow/flow-go/blob/173f14150bc827cf9dcea598f9ae7b5269c09eb2/engine/access/rest/routes/websocket_broker.go#L264-L277
• Provide tests to validate proper detection and handling of connectivity issues.

[Guitarheroua]

@UlyanaAndrukhiv Also, check a chapter for gorilla control messages documentation, to be sure, that ping-pong handles correctly.