feat(core)!: move a bunch of LazyVim features to snacks.nvim (#4706)

## Description

LazyVim comes with a bunch of smaller QoL plugin like features, but it's
not easy for non LazyVim users to use them.

That's why I started working on
[snacks.nvim](https://github.com/folke/snacks.nvim), a collection of
small QoL plugins for Neovim.

Snacks also includes a bunch of new improvements to these features.

This PR fully integrates with snacks.

## Todo

- [ ] add proper deprecations where needed
- [ ] create snacks docs
- [ ] document all the new improvements relevant to LazyVim users

## Closes

- [ ] #4492 
- [ ] #4333
- [ ] #4687

## Screenshots

<!-- Add screenshots of the changes if applicable. -->

## Checklist

- [ ] I've read the
[CONTRIBUTING](https://github.com/LazyVim/LazyVim/blob/main/CONTRIBUTING.md)
guidelines.

lua/lazyvim/plugins/extras/util/gitui.lua

@@ -8,14 +8,14 @@ return {
       {
         "<leader>gG",
         function()
-          LazyVim.terminal.open({ "gitui" }, { esc_esc = false, ctrl_hjkl = false })
+          Snacks.terminal({ "gitui" })
         end,
         desc = "GitUi (cwd)",
       },
       {
         "<leader>gg",
         function()
-          LazyVim.terminal.open({ "gitui" }, { cwd = LazyVim.root.get(), esc_esc = false, ctrl_hjkl = false })
+          Snacks.terminal({ "gitui" }, { cwd = LazyVim.root.get() })
         end,
         desc = "GitUi (Root Dir)",
       },