[Feature] Use the native confirmation dialogue

[musjj]

Is your feature request related to a problem? Please describe.
Right now, this plugin uses a handrolled function to confirm unsaved changes, etc.

Describe the solution you'd like
Vim already has a built-in that can handle this, see: :h confirm.

By using the built-in, the user will have a consistent interface and bindings for all confirmation dialogues, which is cool.

As a plus, plugins that overrides the built-in UI like noice.nvim will automatically integrate with this plugin for free.

Example usage:

:confirm bdelete " vimscript

vim.cmd.bdelete { mods = { confirm = true } } -- lua