Add fff.nvim and replace snacks file picker with it

nvim/lua/plugs/fff.lua

@@ -0,0 +1,14 @@
+return {
+    "dmtrKovalenko/fff.nvim",
+    build = "nix run .#release",
+    -- No need to lazy-load with lazy.nvim.
+    -- This plugin initializes itself lazily.
+    lazy = false,
+    keys = {
+        {
+            "ff", -- try it if you didn't it is a banger keybinding for a picker
+            function() require('fff').find_files() end,
+            desc = 'FFFind files',
+        }
+    }
+}