Use new MaxMind env vars on Labrinth (#4573)

* Bring in modrinth-maxmind

* integrate modrinth-maxmind into labrinth

* Fix CI

packages/modrinth-maxmind/examples/maxmind.rs

@@ -0,0 +1,35 @@
+//! Example/testing binary for checking if a MaxMind database can be loaded from
+//! the current environment.
+
+use std::net::IpAddr;
+
+use eyre::Result;
+use maxminddb::geoip2;
+use modrinth_util::Context;
+use tracing::info;
+
+/// Looks up country details for an IP using the MaxMind database
+#[derive(Debug, clap::Parser)]
+struct Args {
+    /// IP address to look up
+    ip: IpAddr,
+}
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    let args = <Args as clap::Parser>::parse();
+    tracing_subscriber::fmt().init();
+
+    let maxmind = modrinth_maxmind::init_reader()
+        .await
+        .wrap_err("failed to create reader")?;
+
+    let ip = args.ip;
+    let country = maxmind
+        .lookup::<geoip2::Country>(ip)
+        .wrap_err("failed to lookup country")?;
+
+    info!("Country details for {ip:?}:\n{country:#?}");
+
+    Ok(())
+}