add Webpack

[jens1o]

_Fixes #305_

Changes proposed:

• Add
• Prepare
• Delete
• Fix

Things I've done:

• I've pulled the latest master branch
• I've run npm install to install all the dependenies
• I've checked my code, it is clean.
• I've run ESLint.
• My pull request fixes an issue, I referenced the issue.
• My pull request is not too big, otherwise I've already squashed it.
• I've run npm run build to build the extension. (If I had done something with the extension.)

adds webpack.

@robertohuertasm Is it right like this?

[robertohuertasm]

@jens1o it's ok! Sorry for the delay in my answer. I'm a little busy these days... 😞

[jens1o]

Don't worry 😃

[snowgrus]

webpack.config.dev.js or webpack.config.*.js not support

[jens1o]

@wgruis Look here: #313 (comment)