Restructure demo and add linting

[edgesoft]

• move webpack and server.js to demo
• cleanup deps and avoid babel to be applied to forms module
• small fixes in configureField
• update README for new demo refactoring
• linting

[edgesoft]

@Guria It's only the first to linting that should be merged. The UploadSimple needs checks.

[Guria]

Great work. Are you ready for some git rebase fun?

fix: errorMessages was not set on field 86df6e7 // hard to find what was fixed, because of style changes docs(readme): update demo run instructions cc069ff // no past tense chore: add standard as linting 2f4866a // no past tense style: apply feross/standart js codestyle dca8416 // use style for fixing codestyle style: remove redundant else clause dfc49b5 // could be squashed to previous chore(demo): upload files validation demo eb23c1d // define scope, no past tense, squash commits: 6435f3a, d1edd04, 175d3ec, b580397