Update Purr config; Add Miniflux service

nix/application/miniflux.nix

@@ -0,0 +1,11 @@
+{ pkgs, config, ...}: {
+  services.miniflux = {
+    enable = true;
+    adminCredentialsFile = config.age.secrets.miniflux.path;
+    config = {
+      CLEANUP_FREQUENCY_HOURS = "72";
+      LISTEN_ADDR = "0.0.0.0:26343";
+      BASE_URL = "https://flux.matri.cx";
+    };
+  };
+}