emmet-ls support

### Describe your request

Currently `:lang web` and `:lang javascript` have Emmet support with emmet-mode.
But emmet-mode has no fuzzy matching which is a very important feature cause to help us to remember the abbreviations for CSS properties.
In addition, the author of [emmet-mode](https://github.com/smihica/emmet-mode) said emmet-mode will be no longer maintained.

So I want emmet-ls support in Doom Emacs.
It works as an add-on LSP server, and provides Emmet expansions as the LSP snippets.

FYI emmet-ls support was merged into lsp-mode via https://github.com/emacs-lsp/lsp-mode/pull/3384.

### Briefly explain its use-case

1. Install Doom Emacs
2. Install emmet-ls
3. Open a CSS file
4. Type some Emmet abbreviation and expand it