Check nvim config for storage/performance

[FrostyNick]

This config is mostly optimized for startup time at the moment.

There are times that loading big files can be not as fast as desired. As a result, I've made this issue.

• If it's related to LSP, then of course it's worth performance hits*.

• If core functionality is missing, keep the feature*.

• If it takes a lot of storage, consider removing. (Looking at you, rainbow-delimiters.nvim, gx.nvim, snacks.nvim .. which combined, take 107 MB of space.)

* if keeping, document performance hits.