CLI command to choose a deployment without deploying

[thomasballinger]

A script like

    "dev": "concurrently -r npm:dev:web npm:dev:convex",

works well every time you run it... except the first time. Then the concurrently script interferes with the interactive startup script, so you need to use

    "dev": "npx convex dev --once && concurrently -r npm:dev:web npm:dev:convex",

But that script is slow every time after.

We used to have a npx convex init command we'd run before this like npx convex init, do we need to bring this back?