Upgrade to react-intl v5

[jmsv6d]

Feature Request

As part of terra-application v2, react-intl needs to be upgraded to v5. As part of this upgrade terra-base and terra-i18n will be deprecated with their functionality moving to terra-application-base.

Description

The work for this has been started here: https://github.com/cerner/terra-application/tree/react-intl-take-2
There has also been work on updating the loaders here: https://github.com/cerner/terra-aggregate-translations
We might want to discontinue generating the loader file and dynamically import locale data in terra-application-base as well. This would significantly simplify the logic around loading the locales.

Additional Context / Screenshots

@ Mentions

[jmsv6d]

Closed with #124