chore: segregate internal logic to a package

[fernandezcuesta]

The purpose here is to allow importing most of P&T logic into other functions, suck as function-environment-config (see discussion).
Per-se this should be a no-op.

[negz]

I'm not inclined to approve this - it'd require the maintainers of this function to commit to supporting the P&T logic as a library. That's a different and larger commitment from supporting the function itself.

[fernandezcuesta]

Yeah I understood this is not the correct approach right after reading the discussion on slack about crank in v2, where essentially a similar approach was discouraged.
Agree on that, closing.

Thanks!