Check for existence of api directory when running dev and skip api and db tasks if it doesn't exist

[cannikin]

For those that only want to deploy the web site, they should be able to delete /api completely and still be able to run yarn rw dev locally. Right now the api and db tasks raise all kinds of errors.

[ackinc]

Hi @cannikin , I've taken a first stab at this issue

[peterp]

Thanks @ackinc!

The sides PR should deal with this in the long term, but there's no reason why we can't also deal with it in the short term.

[ackinc]

Hey guys, is there anything else you'd like me to do before closing this issue?

I guess the issue wasn't auto-closed because I put 'Closes #483' as a PR comment rather than in the PR description

[thedavidprice]

Thanks again @ackinc

A question before we close this --> has anyone locally tested #490 to confirm it works?

Currently, it seems the Prisma Client is always being generated, correct? I can't imagine it doesn't freak out if the API directory doesn't exist:
https://github.com/ackinc/redwood/blob/64826b2a345e98cf66dad5dcdfcc17c9c7f60217/packages/cli/src/commands/dev.js#L24

[thedavidprice]

Heads up here --> Tested locally and Prisma client is throwing errors. Web dev-server is not blocked from running.

$ yarn rw dev
yarn run v1.22.4
$ /Users/price/Repos/xx-delete/node_modules/.bin/rw dev
  ✖ Generating the Prisma client...
    → spawn /bin/sh ENOENT
Command failed with ENOENT: yarn prisma generate
spawn /bin/sh ENOENT
$ /Users/price/Repos/xx-delete/node_modules/.bin/webpack-dev-server --config ../node_modules/@redwoodjs/core/config/webpack.development.js
17:21:35 web | ℹ ｢wds｣: Project is running at http://localhost:8910/
17:21:35 web | ℹ ｢wds｣: webpack output is served from /
17:21:35 web | ℹ ｢wds｣: Content not from webpack is served from /Users/price/Repos/xx-delete/web
17:21:35 web | ℹ ｢wds｣: 404s will fallback to /index.html

I'll see about getting a PR with a fix.