feat(extras): expose prios to users for customization (#4587)

## Description
Offer to users capability to customize priorities of the Extras.
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  why we should accept this pull request. -->

## Related Issue(s)
Closes #4584
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## Screenshots

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## Checklist

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

lua/lazyvim/plugins/xtras.lua

@@ -10,6 +10,10 @@ local prios = {
   ["lazyvim.plugins.extras.editor.outline"] = 100,
 }
 
+if vim.g.xtras_prios then
+  prios = vim.tbl_deep_extend("force", prios, vim.g.xtras_prios or {})
+end
+
 ---@type string[]
 local extras = LazyVim.dedup(LazyVim.config.json.data.extras)