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/cl-colors.nix

@@ -0,0 +1,24 @@
+{
+  depot ? import <depot> {},
+  universe ? import <universe> {},
+  ...
+}:
+
+let
+  src = builtins.fetchGit {
+    url = "https://github.com/tpapp/cl-colors.git";
+    rev = "827410584553f5c717eec6182343b7605f707f75";
+  };
+in depot.nix.buildLisp.library {
+  name = "cl-colors";
+  deps = [
+    depot.third_party.lisp.alexandria
+    universe.third_party.lisp.let-plus
+  ];
+  srcs = [
+    "${src}/package.lisp"
+    "${src}/colors.lisp"
+    "${src}/colornames.lisp"
+    "${src}/hexcolors.lisp"
+  ];
+}