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/ui/edgy.lua

@@ -31,14 +31,6 @@ return {
               return vim.api.nvim_win_get_config(win).relative == ""
             end,
           },
-          {
-            ft = "lazyterm",
-            title = "LazyTerm",
-            size = { height = 0.4 },
-            filter = function(buf)
-              return not vim.b[buf].lazyterm_cmd
-            end,
-          },
           "Trouble",
           { ft = "qf", title = "QuickFix" },
           {
@@ -103,6 +95,7 @@ return {
         end
       end
 
+      -- trouble
       for _, pos in ipairs({ "top", "bottom", "left", "right" }) do
         opts[pos] = opts[pos] or {}
         table.insert(opts[pos], {
@@ -116,6 +109,22 @@ return {
           end,
         })
       end
+
+      -- snacks terminal
+      for _, pos in ipairs({ "top", "bottom", "left", "right" }) do
+        opts[pos] = opts[pos] or {}
+        table.insert(opts[pos], {
+          ft = "snacks_terminal",
+          size = { height = 0.4 },
+          title = "%{b:snacks_terminal.id}: %{b:term_title}",
+          filter = function(_buf, win)
+            return vim.w[win].snacks_win
+              and vim.w[win].snacks_win.position == pos
+              and vim.w[win].snacks_win.relative == "editor"
+              and not vim.w[win].trouble_preview
+          end,
+        })
+      end
       return opts
     end,
   },