Switch to new lazy-based config

Still a bit WIP. Gradually adding back old plugins and config from old config.

lua/plugins/luasnip.lua

@@ -0,0 +1,7 @@
+-- Disable <tab> and <s-tab> behavior in luasnip for supertab: https://www.lazyvim.org/configuration/recipes#supertab
+return {
+  "L3MON4D3/LuaSnip",
+  keys = function()
+    return {}
+  end,
+}