`nvim-dap`/`-ui` support

[Iron-E]

From https://github.com/Iron-E/nvim-highlite/issues/25#issuecomment-1527676820:

I was never able to get [nvim-dap] working correctly. If you feel like contributing the groups for nvim-dap/-ui, I'd be happy to help answer any questions you have.

I'll keep this issue open until either one of the following occurs:

• [ ] Confirmation that nvim-dap/-ui work as expected without explicit support.
• [ ] Explicit support for nvim-dap/-ui is added.

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cc @Zane-