feat(ai): add folke/sidekick.nvim

[ALameLlama]

Closes #1655

📑 Description

Add sidekick.nvim

📖 Additional Information

This is still WIP and I still need to test a lot of this

[github-actions]

Review Checklist

Does this PR follow the [Contribution Guidelines](development guidelines)? Following is a partial checklist:

Proper conventional commit scoping:

• If you are adding a new plugin, the scope would be the name of the category it is being added into. ex. feat(utility): added noice.nvim plugin

• If you are modifying a pre-existing plugin or pack, the scope would be the name of the plugin folder. ex. fix(noice-nvim): fix LSP handler error

• Pull request title has the appropriate conventional commit type and scope where the scope is the name of the pre-existing directory in the project as described above

• README is properly formatted and uses fenced in links with <url> unless they are inside a [title](url)

• Entry returns a single plugin spec with the new plugin as the only top level spec (not applicable for recipes or packs).

• Proper usage of opts table rather than setting things up with the config function.

• Proper usage of specs table for all specs that are not dependencies of a given plugin (not applicable for recipes or packs).

[Yorizel]

if you use copilot.vim the lsp stuff is also handled for you

[Yorizel]

maybe we could use autoCmds, or make the nes features fullly dependent on the copilot.vim or copilot.lua

[ALameLlama]

the plugin does have a way to enable/disable this via the vim.g.sidekick_nes so we could let the use decide if it should be enabled or not
https://github.com/folke/sidekick.nvim/blob/main/lua/sidekick/config.lua#L18

Or if we want a better out of the box experience, we can probably check if the copilot lsp is installed and then enabled it instead of force installing the lsp since not everyone might want this and might just want to use the cli side

[Yorizel]

Can I use this without NES, just for CLI tools?

Absolutely! Just disable NES:

opts = {
  nes = { enabled = false },
}

Maybe we can just disable it by default and enable it with the copilt.lua and copilot.vim marked as optional