feat(3p/lisp): Add many packages

Add the following packages along with their transitive dependencies:
- trivial-ldap
- defclass-std
- easy-routes

Change-Id: Ib24517f18d14d57540362132c9a24ff2a5a4bd9d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1336
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: kanepyork <rikingcoding@gmail.com>

third_party/lisp/defclass-std.nix

@@ -0,0 +1,19 @@
+{ depot, pkgs, ... }:
+
+let src = pkgs.fetchFromGitHub {
+    owner = "EuAndreh";
+    repo = "defclass-std";
+    rev = "0300f171c1308e5ff3efd66b4f4e766f2bcde259";
+    sha256 = "0ggzh80ajx4k6w5c3xprnd7m27q5hx9xx9lxs4jv0pbrlg18ijcw";
+  };
+in depot.nix.buildLisp.library {
+  name = "defclass-std";
+  deps = with depot.third_party.lisp; [
+    alexandria
+    anaphora
+  ];
+
+  srcs = map (f: src + ("/src/" + f)) [
+    "defclass-std.lisp"
+  ];
+}