feat(neovim): started rust configuration and tweaked some lsp stuff

.config/nvim/lua/custom/plugins/rustaceanvim.lua

@@ -0,0 +1,8 @@
+return {
+    'mrcjkb/rustaceanvim',
+    version = '^4',
+    lazy = false, -- already lazy
+    init = function ()
+        require("custom.config.rustaceanvim")
+    end
+}