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.

universe/blog/default.nix

@@ -1,28 +0,0 @@
-{
-  nixpkgs ? import <nixpkgs> {},
-  depot ? import <depot> {},
-  universe ? import <universe> {},
-  ...
-}:
-
-let
-  injectedPosts = nixpkgs.writeText "posts.lisp" ''
-    (in-package #:server)
-    (setq *path-to-posts* "${./posts}")
-  '';
-  injectedExecutables = nixpkgs.writeText "executables.lisp" ''
-    (in-package #:server)
-    (setq *pandoc-bin* "${nixpkgs.pandoc}/bin/pandoc")
-  '';
-in depot.nix.buildLisp.program {
-  name = "server";
-  deps = with depot.third_party.lisp; with universe.third_party.lisp; [
-    hunchentoot
-    cl-arrows
-  ];
-  srcs = [
-    ./src/server.lisp
-    injectedPosts
-    injectedExecutables
-  ];
-}