feat(panettone): announce newly created issues using irccat

- The new PANETTONE.IRC package contains the SEND-IRC-NOTIFICATION function,
  which opens a new TCP socket to irccat (if it's running and configured) in
  order to announce the creation of new issues.
- The IRCCATHOST and IRCCATPORT environment variables must be set for this to
  work.
- Additionally, the ISSUECHANNEL environment variable may be used to direct
  announcements at a given channel (otherwise it'll just use the first one).

Change-Id: I429a66f24d0f80ed10db173d6af7105fb1d3d023
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2077
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>

web/panettone/src/panettone.lisp

@@ -450,10 +450,14 @@
       (render/issue-form
        (make-instance 'model:issue :subject subject :body body)
        "Subject is required")
-      (progn
-        (model:create-issue :subject subject
-                            :body body
-                            :author-dn (dn *user*))
+      (let ((issue
+              (model:create-issue :subject subject
+                                  :body body
+                                  :author-dn (dn *user*))))
+        (send-irc-notification (format nil "b/~A: \"~A\" opened by ~A - https://b.tvl.fyi/issues/~A"
+                                       (issue-id issue) subject (dn *user*)
+                                       (issue-id issue))
+                               :channel (uiop:getenvp "ISSUECHANNEL"))
         (hunchentoot:redirect "/"))))
 
 (defroute show-issue