Flakeify home config

Use nix flakes instead of niv for pinning dependency channels.

First step towards merging my "nixos-system" and "nixos-home"
configs into a single trivially reproducible flake setup.

Apply home config via:

> nix build .#homeManagerConfigurations.common.activationPackage --impure
> ./result/activate

1 files changed, 0 insertions, 75 deletions

diff --git a/nix/sources.json b/nix/sources.json
deleted file mode 100644
index b86348f..0000000
--- a/nix/sources.json
+++ /dev/null
@@ -1,75 +0,0 @@
-{
-    "emacs-overlay": {
-        "branch": "master",
-        "description": "Bleeding edge emacs overlay [maintainer=@adisbladis] ",
-        "homepage": "",
-        "owner": "nix-community",
-        "repo": "emacs-overlay",
-        "rev": "9da066d11fbedda841cae9d06c5391e1ebd65801",
-        "sha256": "16jc0653m1azaqbz5gbj92amqmj2kb44j1jvvmrlk45v9679fwfl",
-        "type": "tarball",
-        "url": "https://github.com/nix-community/emacs-overlay/archive/9da066d11fbedda841cae9d06c5391e1ebd65801.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "home-manager": {
-        "branch": "release-21.05",
-        "description": "Manage a user environment using Nix",
-        "homepage": "https://rycee.gitlab.io/home-manager/",
-        "owner": "rycee",
-        "repo": "home-manager",
-        "rev": "9c0abed5228d54aad120b4bc757b6f5935aeda1c",
-        "sha256": "05pfa26p9k1gpir9sniwg195cqqc9v6yp9b5f9hrjhlh3jm14bgq",
-        "type": "tarball",
-        "url": "https://github.com/rycee/home-manager/archive/9c0abed5228d54aad120b4bc757b6f5935aeda1c.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
-        "version": "20.03"
-    },
-    "mypkgs": {
-        "branch": "master",
-        "description": "Some custom Nix derivations",
-        "homepage": null,
-        "owner": "KnairdA",
-        "repo": "pkgs",
-        "rev": "122a6169f67f2b996b529ef2be6c4dbd74d4b166",
-        "sha256": "1yxlg9imhqaw2a0db6lqxax3s2di6f02gmjjapb2p2achvx302f1",
-        "type": "tarball",
-        "url": "https://github.com/KnairdA/pkgs/archive/122a6169f67f2b996b529ef2be6c4dbd74d4b166.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "niv": {
-        "branch": "master",
-        "description": "Easy dependency management for Nix projects",
-        "homepage": "https://github.com/nmattia/niv",
-        "owner": "nmattia",
-        "repo": "niv",
-        "rev": "e0ca65c81a2d7a4d82a189f1e23a48d59ad42070",
-        "sha256": "1pq9nh1d8nn3xvbdny8fafzw87mj7gsmp6pxkdl65w2g18rmcmzx",
-        "type": "tarball",
-        "url": "https://github.com/nmattia/niv/archive/e0ca65c81a2d7a4d82a189f1e23a48d59ad42070.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "nixpkgs": {
-        "branch": "nixos-21.05",
-        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
-        "homepage": "https://github.com/NixOS/nixpkgs",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "973910f5c31b9ba6c171c33a8bd7199990b14c72",
-        "sha256": "1n1kibmn1fcjazaxp8lydwdx646lknqksv5b2fm33fdq2dvafvj7",
-        "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/973910f5c31b9ba6c171c33a8bd7199990b14c72.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "nixpkgs-unstable": {
-        "branch": "nixpkgs-unstable",
-        "description": "Nix Packages collection",
-        "homepage": null,
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "ecaf3da9340231e5493eccc3db87604a3705da42",
-        "sha256": "049dcpzklpjj0c7g172njfcqb9xvxkpyf7qjiwvaf8klgd5cippa",
-        "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/ecaf3da9340231e5493eccc3db87604a3705da42.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    }
-}