nickserv: add INFO and ALIST

INFO shows an account's registration date and (to its owner) email; ALIST
lists the channels an account founds or has access on. The UTC time
formatter moves to the db module so both services share it.

modules/nickserv/alist.rs

@@ -0,0 +1,27 @@
+use crate::engine::db::Db;
+use crate::engine::service::{Sender, ServiceCtx};
+
+// ALIST: list the channels the sender's account founds or has access on.
+pub fn handle(me: &str, from: &Sender, ctx: &mut ServiceCtx, db: &Db) {
+    let Some(account) = from.account else {
+        ctx.notice(me, from.uid, "You need to be logged in. Identify to NickServ first.");
+        return;
+    };
+    let mut rows: Vec<(String, &str)> = Vec::new();
+    for c in db.channels() {
+        if c.founder.eq_ignore_ascii_case(account) {
+            rows.push((c.name.clone(), "founder"));
+        } else if let Some(a) = c.access.iter().find(|a| a.account.eq_ignore_ascii_case(account)) {
+            rows.push((c.name.clone(), if a.level == "voice" { "voice" } else { "op" }));
+        }
+    }
+    if rows.is_empty() {
+        ctx.notice(me, from.uid, "You have access on no channels.");
+        return;
+    }
+    rows.sort_by(|a, b| a.0.cmp(&b.0));
+    ctx.notice(me, from.uid, format!("Channels you have access on ({}):", rows.len()));
+    for (chan, role) in rows {
+        ctx.notice(me, from.uid, format!("  \x02{chan}\x02 ({role})"));
+    }
+}