Update Onboarding Processes in Readmes.

Try spinning the project up from scratch using both the main readme and the front end readme.

- clarify and update as necessary

### For the frontend Readme, there is definitely a bug

the on-boarding process should prompt running
- `script/server` (getting all three docker containers built)
- `script/update` (seed the db and such)
- `yarn dev` run the dev server for HMR

Update the readmes, then test/double check for accuracy.
add clarifying steps if necessary