Improve Error Messages

[brkp]

This PR introduces context messages for each error message, providing additional information to help understand the cause of the error. Here's an example before/after:

Before:

[2023-01-02T13:15:03Z INFO  mmproxy::listener::tcp] listening on: 127.0.0.1:25577
[2023-01-02T13:15:06Z INFO  mmproxy::listener::tcp] [new conn] [origin: 127.0.0.1:53566 [src: 127.0.0.1:0]
[2023-01-02T13:15:06Z ERROR mmproxy::listener::tcp] while handling a connection: Operation not permitted (os error 1)

After:

[2023-01-02T13:12:59Z INFO  mmproxy::listener::tcp] listening on: 127.0.0.1:25577
[2023-01-02T13:13:16Z INFO  mmproxy::listener::tcp] [new conn] [origin: 127.0.0.1:46780] [src: 127.0.0.1:0]
[2023-01-02T13:13:16Z ERROR mmproxy::listener::tcp] failed to set ip transparent on the upstream socket: Operation not permitted (os error 1)

[markus-wa]

LGTM - feel free to merge if the PR is ready from your side 🙂