Refactor proxy

[mostafa]

The proxy has a few issues that need to be addressed before it can be further enhanced:

v0.8.x milestone:

• [x] gatewayd-io/gatewayd#359
• [x] gatewayd-io/gatewayd#343 (enable bidirectional communication)
• [x] gatewayd-io/gatewayd#33 (async communication)

v0.9.x milestone:

• [ ] #425
• [ ] gatewayd-io/gatewayd#399
  • [x] gatewayd-io/gatewayd#422
  • [ ] gatewayd-io/gatewayd#398
  • [ ] gatewayd-io/gatewayd#55

Related

• #206