Feat/587-circuit-relay (#611)

* feat: implemented setup of circuit relay and test cases

* chore: remove test files to be rewritten

* added 1 test suite for protocol

* added 1 test suite for discovery

* fixed protocol timeouts and message types to handle reservations and stream operations.

* Resolved merge conflict in libp2p/tools/utils.py by combining timeout approach with retry mechanism

* fix: linting issues

* docs: updated documentation with circuit-relay

* chore: added enums, improved typing, security and examples

* fix: created proper __init__ file to ensure importability

* fix: replace transport_opt with listen_addrs in examples, fixed typing and improved code

* fix type checking issues across relay module and test suite

* regenerated circuit_pb2 file protobuf version 3

* fixed circuit relay example and moved imports to top in test_security_multistream

* chore: moved imports to the top

* chore: fixed linting of test_circuit_v2_transport.py

---------

Co-authored-by: Manu Sheel Gupta <manusheel.edu@gmail.com>

libp2p/relay/circuit_v2/protocol_buffer.py

@@ -0,0 +1,55 @@
+"""
+Protocol buffer wrapper classes for Circuit Relay v2.
+
+This module provides wrapper classes for protocol buffer generated objects
+to make them easier to work with in type-checked code.
+"""
+
+from enum import (
+    IntEnum,
+)
+from typing import (
+    Any,
+)
+
+from .pb.circuit_pb2 import Status as PbStatus
+
+
+# Define Status codes as an Enum for better type safety and organization
+class StatusCode(IntEnum):
+    OK = 0
+    RESERVATION_REFUSED = 100
+    RESOURCE_LIMIT_EXCEEDED = 101
+    PERMISSION_DENIED = 102
+    CONNECTION_FAILED = 200
+    DIAL_REFUSED = 201
+    STOP_FAILED = 300
+    MALFORMED_MESSAGE = 400
+    INTERNAL_ERROR = 500
+
+
+def create_status(code: int = StatusCode.OK, message: str = "") -> Any:
+    """
+    Create a protocol buffer Status object.
+
+    Parameters
+    ----------
+    code : int
+        The status code
+    message : str
+        The status message
+
+    Returns
+    -------
+    Any
+        The protocol buffer Status object
+
+    """
+    # Create status object
+    pb_obj = PbStatus()
+
+    # Convert the integer status code to the protobuf enum value type
+    pb_obj.code = PbStatus.Code.ValueType(code)
+    pb_obj.message = message
+
+    return pb_obj