Optimise webpack to reduce bundle size

[goastler]

switch to default imports, e.g.

import Xyz from "blah/Xyz";

instead of

import {Xyz} from "blah";

[forgetso]

Optimisations

Tasks for this issue.

• Absolute imports (see above)
• How do we import absolutely from our own packages? import { encodeStringAddress } from '@prosopo/provider/src/util' or import { encodeStringAddress } from '@prosopo/provider/dist/util'
• Ensure that non-required packages are not bundled by whitelisting packages or some other method.
• What's going with react-jsx? There was an error when whitelisting in the production build.
• Create process for white listing packages in future and ensure that new packages will be added to the white list. (webpack plugin or manually maintained list or something else?)
• Chunk packages appropriately - is cache shared across web pages?
• Create a bundle that does not include react, for websites on which it is already available (optional)

[HughParry]

follow on ticket for improvements, mvp this ticket