fix: make bootstrap check names earlier

[tshauck]

Right now if you enter a bad name initially, you get stuck in a bad state because some of the file updates happen before the name is checked. This PR reorgs the script so that it's generally organized more like a standard python script, but also moves the name validation before the rest of the script so it's less likely an extension creator gets into a bad state.

[samansmink]

Thanks for the PR, good idea! I've pushed a minor workaround to get the Linux CI running

[tshauck]

Thanks!