Running the Tahoe CLI takes 400+ milliseconds just to start

[itamarst]

This may or may not be a priority, but basic tahoe commands take a while to start. Profiling suggests this is just due to code imports.

The ~400ms is from a i7-12700k, so a very fast CPU core. A large percentage of computers will be rather slower.

For many use cases this is OK. If you're doing heavy scripting with `tahoe get' or something this will add up.

Potential solutions are:

• Something like PyOxidizer?, which is designed to package up Python CLIs in ways that make them start faster.
• Rewrite the CLI with a different, faster language?