Get rid of CommonJS dependencies

[manuelwedler]

Since Angular version 10 the Angular cli warns about used CommonJS dependencies, because they can cause larger bundle sizes. See https://angular.io/guide/build#configuring-commonjs-dependencies for reference.

The cli warnings are currently suppressed by the allowedCommonJsDependencies option:

webui/angular.json

Lines 29 to 50 in e091b8a

	"allowedCommonJsDependencies": [
	"bignumber.js",
	"qrcode",
	"ajv",
	"web3",
	"web3-utils",
	"web3-core",
	"web3-core-helpers",
	"web3-core-requestmanager",
	"web3-eth-personal",
	"web3-net",
	"web3-eth",
	"web3-bzz",
	"web3-shh",
	"web3-providers-http",
	"web3-providers-ws",
	"web3-providers-ipc",
	"randombytes",
	"underscore",
	"ethjs-unit",
	"elliptic"
	]

We should try to only use ECMAScript modules in the future. Some dependencies like web3 are already working on providing an ES module.

[manuelwedler]

Using import { BigNumber } from 'bignumber.js/bignumber'; should fix it for bignumber.js, see MikeMcl/bignumber.js#278