upgrade webpack to v4

[mamboer]

1. Update the project dependencies to the latest
2. Fix a circular dependency bug

[yunhan0]

Thank you for your contribution @mamboer! I'll merge your request once I check it out. Cheers!

[yunhan0]

Hi @mamboer, first of all, I wanna say, your upgrade is great! However, to fix the circular dependency, I've noticed few codes are moved to different files. This may lead to confusion. For example, HTTP interceptors has been moved to main.js file. But I think this logic should be kept inside http-common.js.

So I decided to upgrade webpack from 3 to 4 to find out the problem. I got the same Cyclic Error, but turns out it seems to be a problem with a dependency of the html-webpack-plugin. Updating html-webpack-plugin would fix the problem

npm i  html-webpack-plugin@next 

For details about this issue, please check out here.
So, in this way, we don't need to move codes to solve the problem.

Still appreciate a lot to your effort and contribution!

[mamboer]

Nice job, cheers.