feat(nix): nix and back again

I tried Nix, but it had too many downsides so I removed it.

1. Didn't like that all files are immutable and simple config changes
need a complete rebuild.
2. Setting up a new Mac didn't work as smoothly as promised. Not worth
the effort.
3. It sucked a lot to always have to type in the password twice on each
darwin-rebuild
4. It solves problems I never had.

.functions/fgh.sh

@@ -0,0 +1,24 @@
+# Find in files with ripgrep and fzf and open on that line
+# -> Works together with Vim Plugin bogado/file-line
+
+frg() {
+    pattern="${1:-.}"
+    file_glob="${2:-*}"
+
+    result=$(rg "$pattern" --line-number --glob "$file_glob" | fzf --delimiter : --preview 'bat --style=numbers --color=always --highlight-line {2} {1}' --preview-window '+{2}-/2')
+
+    if [ -n "$result" ]; then
+        file=$(echo "$result" | cut -d: -f1)
+        line=$(echo "$result" | cut -d: -f2)
+
+        if command -v nvim >/dev/null 2>&1; then
+            nvim "+${line}" "$file"
+        elif command -v vim >/dev/null 2>&1; then
+            vim "+${line}" "$file"
+        else
+            echo "Neither neovim nor vim is installed."
+        fi
+    else
+        echo "No file selected."
+    fi
+}