Babashka nrepl

[hkupty]

This PR adds a lot of stuff that was minor, but two major things:

• Output buffer for printing nrepl eval communication
• Replaces admin session for a babashka nrepl server if it exists in path

Since the admin session is supposed to be used only for very lightweight operations, babashka is perfect for the task.

Additionally, it allows for frontends (such as jazz.nvim) to spawn babashka nrepl sessions.