Conflicts:
Dockerfile
app/javascript/packs/common.js
config/webpack/loaders/sass.js
config/webpack/shared.js
db/schema.rb
package.json
yarn.lock
A lot of the conflicts come from updating webpack.
Even though upstream deleted app/javascript/packs/common.js, I kept
glitch-soc's version as it unifies JS/CSS packs behavior across flavours.
Ported glitch changes to webpack 4.x
