Run axe-core/react in development as part of frontend-platform

[davidjoy]

https://github.com/dequelabs/axe-core-npm/blob/develop/packages/react/README.md

axe-core is an accessibility testing library. In an effort to continue to support and promote accessible user experiences, we'd like to automatically run axe-core/react as part of development servers. The easiest way to enable this across MFEs would probably be to add it to frontend-platform as an optional service that starts during development (getConfig().ENVIRONMENT === 'development')

One subtlety here is removing the dependency in production, as it's quite large. The best way to do this, I think, is to conditionally load it using an import() function if we're in a development environment. During the build, webpack will ensure that the library is split out into its own file/chunk. This chunk will get deployed to prod, but won't run because it'll never be loaded. This seems like a fine compromise.