Fix Docker build

[eliandoran]

This is a follow-up of #192 (thanks to @chesspro13), focusing strictly on fixing the Docker build.

I started it from scratch because I had some errors at startup I could not understand, more specifically:

Error: Router not found for request GET /assets/v0.63.5/stylesheets/style.css
    at /usr/src/app/src/routes/error_handlers.js:15:19
    at Layer.handle [as handle_request] (/usr/src/app/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/usr/src/app/node_modules/express/lib/router/index.js:328:13)
    at /usr/src/app/node_modules/express/lib/router/index.js:286:9
    at Function.process_params (/usr/src/app/node_modules/express/lib/router/index.js:346:12)
    at next (/usr/src/app/node_modules/express/lib/router/index.js:280:10)
    at Layer.handle [as handle_request] (/usr/src/app/node_modules/express/lib/router/layer.js:91:12)
    at trim_prefix (/usr/src/app/node_modules/express/lib/router/index.js:328:13)
    at /usr/src/app/node_modules/express/lib/router/index.js:286:9
    at Function.process_params (/usr/src/app/node_modules/express/lib/router/index.js:346:12) {
  status: 404
}

Turns out we were missing some files:

In the original:

/usr/src/app/src/public # ls
app-dist              manifest.webmanifest  stylesheets
fonts                 robots.txt

But in our Docker image we have only:

/usr/src/app/src/public # ls
app-dist

Similarly we were missing the front-end files:

/usr/src/app/src/public/app-dist # ls
317.js                  760.js.map              mobile.js
317.js.map              784.js                  mobile.js.map
41.js                   784.js.map              setup.js
41.js.map               desktop.js              setup.js.map
749.js                  desktop.js.LICENSE.txt  share.js
749.js.map              desktop.js.map
760.js                  doc_notes

Ended up using a slightly different approach: we copy everything but the TypeScript files, then build the TypeScript files and copy those into the src folder.

[chesspro13]

Here's to finally having a product!