chore(proxy): demote a ton of logs for successful connection attempts (#9803)

See https://github.com/neondatabase/cloud/issues/14378

In collaboration with @cloneable and @awarus, we sifted through logs and
simply demoted some logs to debug. This is not at all finished and there
are more logs to review, but we ran out of time in the session we
organised. In any slightly more nuanced cases, we didn't touch the log,
instead leaving a TODO comment.

proxy/src/bin/local_proxy.rs

@@ -125,6 +125,7 @@ async fn main() -> anyhow::Result<()> {
 
     Metrics::install(Arc::new(ThreadPoolMetrics::new(0)));
 
+    // TODO: refactor these to use labels
     debug!("Version: {GIT_VERSION}");
     debug!("Build_tag: {BUILD_TAG}");
     let neon_metrics = ::metrics::NeonMetrics::new(::metrics::BuildInfo {

proxy/src/bin/proxy.rs

@@ -288,6 +288,7 @@ async fn main() -> anyhow::Result<()> {
     let _panic_hook_guard = utils::logging::replace_panic_hook_with_tracing_panic_hook();
     let _sentry_guard = init_sentry(Some(GIT_VERSION.into()), &[]);
 
+    // TODO: refactor these to use labels
     info!("Version: {GIT_VERSION}");
     info!("Build_tag: {BUILD_TAG}");
     let neon_metrics = ::metrics::NeonMetrics::new(::metrics::BuildInfo {