move tooling into root & stop shipping eslint with CLI

[xavdid]

rOk! So this is tacking some monorepo tooling debt we hadn't gotten around to doing. The PR is pretty noisy, so i'll summarize the important changes:

1. added a root .eslintrc
2. in each of the 4 main package.jsons:
   a. moved lint, test, and smoke-test into a single command: validate
   b. removed posttest: "yarn lint"
3. added zapier-platform-example-app- to the name of the 3 oauth1 examples. This doesn't change init behavior (we were looking them up by folder name, not package.json/name), but does let us easily ignore them in the root lerna commands
4. removed .eslintrc and yarn.lock from all sub-packages
5. pulled a lot of devDeps out of sub packages so they'll all use the same version in root
6. removed eslint app linting from CLI (only actual code change)

Notes

1. I've verified locally that tests pass.
2. Linting (and thus CI) will fail, since I didn't want to add more noise to already noisy PR. Once it's ✅, i'll fix all the linting issues. it's mostly using const instead of let and spacing after comments (// asdf instead of //asdf).
3. We should probably mark master branch as protected, since this is not the first time I've accidentally pushed straight there. I think i've scrubbed that history correctly.

[eliangcs]

Awesome, thanks for cleaning this up!

On your note (3), yes, I think we can mark master branch as protected. Feel free to go for it.

[eliangcs]

The trailing spaces were re-added in my last PR. I don't know why they keep coming back. 🤷‍♂ Maybe your IDE automatically strips trailing spaces for all files in the repo? Mine only does that to a file when it's saved.