all: remove TODOs.md in favor of git-bug

TODOs.md

@@ -1,11 +0,0 @@
-- [ ] Build standalone `xin` tool for ci / deployment.
-- [ ] Add smarter checks
-
-# Example of automated checks from Lily Foster in the NixOS matrix room.
-```
-   checks = with unstable.lib;
-     foldl' recursiveUpdate { } (mapAttrsToList (name: system: {
-       "${system.pkgs.stdenv.hostPlatform.system}"."${name}" =
-         system.config.system.build.toplevel;
-     }) self.nixosConfigurations);
-```