neovim runner

[jonmorehouse]

Let's add a neovim runner which allows us to send output to a neovim buffer.

This will involve finding or creating the neovim term buffer and then calling a shell command that points to the flow script from within it.

[Skyfold]

You might want to create the neovim buffer with some kind of token in the buffer name so the script knows where to run subsequent commands. To make the script easier to write, why not let the user define a term buffer name and set what commands should be run in the buffer.