fix(logging): add flow to persistent logs fields

[lsampras]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

• Adding flow to the persistent keys in subscriber layer
• Adding flow to the middle ware log

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

• Adding flow to the persistent keys in api's

How did you test it?

run the application locally
all api requests should have the following log line at the end of request

• the fields should be populated when available
• These log line will be generated even for health & non-existent paths (e.g / or /favicon.ico)

{
    "message": "[GOLDEN_LOG_LINE - EVENT] REQUEST MIDDLEWARE END",
    "hostname": "<MY_MACHINE>.local",
    "pid": 62901,
    "env": "development",
    "level": "INFO",
    "target": "router::middleware",
    "service": "router",
    "line": 61,
    "file": "crates/router/src/middleware.rs",
    "fn": "golden_log_line",
    "full_name": "router::middleware::golden_log_line",
    "flow": "PaymentsCreate",
    "time": "2024-01-24T06:35:06.771569000Z",
    "merchant_id": "merchant_1706060159",
    "request_id": "018d3a2d-e583-7581-8992-8596b3052995",
    "extra": {
        "trace_id": "00000000000000000000000000000000",
        "http.method": "POST",
        "http.route": "/payments",
        "http.flavor": "1.1",
        "http.user_agent": "PostmanRuntime/7.33.0",
        "payment_id": "payment_intent_id = \"pay_y8XHx5whOaWTdoGrgAAf\"",
        "otel.name": "HTTP POST /payments",
        "http.client_ip": "::1",
        "http.host": "localhost:8080",
        "http.target": "/payments",
        "http.scheme": "http",
        "otel.kind": "server"
    }
}

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible
• I added a CHANGELOG entry if applicable