Remove dependency on webpack, serverless-webpack

[adieuadieu]

Given that Serverless 0.16.0 added a feature which omits devDependencies from the deployment packages, we should just remove the webpack dependency entirely. No real need to minify the code. We can use babel directly in a deploy package script. Or switch to roll-up or something that isn't more targeted towards Browsers. Seems kind of silly to use webpack when deploying to Lambda.