Move nut-score into website/sandbox

Also move some .gitignore entries from the top-level .gitignore into a
subdirectory .gitignore.

.gitignore

@@ -32,12 +32,4 @@ __pycache__
 node_modules/
 /configs/.config/fish/config.fish
 /configs/.config/fish/fish_variables
-/website/blog/public/
-
-# ReasonML
-.merlin
-.bsb.lock
-npm-debug.log
-/nut-score/lib/bs/
-/nut-score/node_modules/
-/nut-score/bundleOutput/
+/website/blog/public/

website/sandbox/nut-score/.gitignore

@@ -0,0 +1,6 @@
+.merlin
+.bsb.lock
+.npm-debug.log
+/lib/bs/
+/node_modules/
+/bundleOutput/