Build: Rename prepare to prep for npm8 and verdaccio

[shilman]

Issue: N/A

What I did

In npm8 publishing packages to the local registry will cause each package to be rebuilt. Our dev workflow assumes that packages are built in a separate step, so building them during publish only slows things down and introduces inconsistencies.

This PR:

• Renames prepare in each package to prep
• Updates the bootstrap script

Self-merging @yannbf @IanVS @joshwooding

How to test

code code
yarn build --core
yarn local-registry --publish  --open

[joshwooding]

Nice!