Splice ./universe directory into ./

Manually merging:
- README.md: I added the description from universe/README.md into the heading of
  dotfiles/README.md.
- .envrc: dotfiles/.envrc was a superset of universe/.envrc
- .gitignore: Adding some of the ignored patterns from universe/.gitignore to
  dotfiles/.gitignore

Everything else here should be a simple rename.

third_party/lisp/anaphora.nix

@@ -0,0 +1,17 @@
+{ depot ? import <depot> {}, ... }:
+
+let
+  src = builtins.fetchGit {
+    url = "https://github.com/tokenrove/anaphora.git";
+    rev = "aeace4c68cf55098a67112750b28f8f2dc6d0e30";
+  };
+in depot.nix.buildLisp.library {
+  name = "anaphora";
+  deps = [];
+  srcs = [
+    "${src}/packages.lisp"
+    "${src}/early.lisp"
+    "${src}/symbolic.lisp"
+    "${src}/anaphora.lisp"
+  ];
+}