[Feature Request]: Commands for "Close all buffers" and "Close All Buffers Except Current"

[andy-bell101]

What?

I'd like some commands to be able to close all the buffers in my workspace, and one to close all but the current buffer.

Why?

The neovim builtin commands for closing buffers (e.g. :%bd) mess too much with my workspace. Bufferline already has commands for closing buffers in a more intelligent way, so it seems like a logical place to add some extra functionality.

[andy-bell101]

Exposing some internals in #583 that will allow users to do this themselves