less verbose info-level logging

[jkarneges]

Pushpin logs a bunch of lines at info-level on startup that are internal and/or typically not interesting. To make the UX a little cleaner, this PR changes the levels on these lines to debug-level. Additionally, handler logging when publishing is reduced from 2 lines to 1 line, connmgr logging doesn't include the rust module (unless level >= debug), and ^C is removed from output on termination.

Resulting start/stop:

% ./pushpin                                     
using config: "/Users/jkarneges/dev/pushpin/config/pushpin.conf"
[INFO] 2024-07-01 14:47:26.898 [connmgr] listening on 0.0.0.0:7999
[INFO] 2024-07-01 14:47:27.008 [handler] http control server: 127.0.0.1:5561
[INFO] 2024-07-01 14:47:27.009 [handler] started
[INFO] 2024-07-01 14:47:27.011 [proxy] routes loaded with 7 entries
[INFO] 2024-07-01 14:47:27.018 [proxy] started
[INFO] 2024-07-01 14:47:27.032 [connmgr] started
signal received: termination signal received
[INFO] 2024-07-01 14:47:28.182 [proxy] stopping...
[INFO] 2024-07-01 14:47:28.182 [handler] stopping...
[INFO] 2024-07-01 14:47:28.181 [connmgr] stopping...