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/util/terminal.lua

@@ -1,13 +1,5 @@
 ---@class lazyvim.util.terminal
----@overload fun(cmd: string|string[], opts: LazyTermOpts): LazyFloat
-local M = setmetatable({}, {
-  __call = function(m, ...)
-    return m.open(...)
-  end,
-})
-
----@type table<string,LazyFloat>
-local terminals = {}
+local M = {}
 
 ---@param shell? string
 function M.setup(shell)
@@ -40,58 +32,4 @@ function M.setup(shell)
   end
 end
 
----@class LazyTermOpts: LazyCmdOptions
----@field interactive? boolean
----@field esc_esc? boolean
----@field ctrl_hjkl? boolean
-
--- Opens a floating terminal (interactive by default)
----@param cmd? string[]|string
----@param opts? LazyTermOpts
-function M.open(cmd, opts)
-  opts = vim.tbl_deep_extend("force", {
-    ft = "lazyterm",
-    size = { width = 0.9, height = 0.9 },
-    backdrop = LazyVim.has("edgy.nvim") and not cmd and 100 or nil,
-  }, opts or {}, { persistent = true }) --[[@as LazyTermOpts]]
-
-  local termkey = vim.inspect({ cmd = cmd or "shell", cwd = opts.cwd, env = opts.env, count = vim.v.count1 })
-
-  if terminals[termkey] and terminals[termkey]:buf_valid() then
-    terminals[termkey]:toggle()
-  else
-    terminals[termkey] = require("lazy.util").float_term(cmd, opts)
-    local buf = terminals[termkey].buf
-    vim.b[buf].lazyterm_cmd = cmd
-    if opts.esc_esc == false then
-      vim.keymap.set("t", "<esc>", "<esc>", { buffer = buf, nowait = true })
-    end
-    if opts.ctrl_hjkl == false then
-      vim.keymap.set("t", "<c-h>", "<c-h>", { buffer = buf, nowait = true })
-      vim.keymap.set("t", "<c-j>", "<c-j>", { buffer = buf, nowait = true })
-      vim.keymap.set("t", "<c-k>", "<c-k>", { buffer = buf, nowait = true })
-      vim.keymap.set("t", "<c-l>", "<c-l>", { buffer = buf, nowait = true })
-    end
-
-    vim.keymap.set("n", "gf", function()
-      local f = vim.fn.findfile(vim.fn.expand("<cfile>"))
-      if f ~= "" then
-        vim.cmd("close")
-        vim.cmd("e " .. f)
-      end
-    end, { buffer = buf })
-
-    vim.api.nvim_create_autocmd("BufEnter", {
-      buffer = buf,
-      callback = function()
-        vim.cmd.startinsert()
-      end,
-    })
-
-    vim.cmd("noh")
-  end
-
-  return terminals[termkey]
-end
-
 return M