manage packages in generated project differently

[bboynton97]

use requirements.txt in projects instead of poetry to support conda and uv.

add a flag to use poetry, but default to reqs

resolves #40

[the-praxs]

Use pyproject.toml for easy conda support without any other package manager.

[bboynton97]

@the-praxs i'd definitely like to use pyproject.toml still but probably need to stop using the poetry tag for deps