Remove post install script from terra-i18n

[bjankord]

Feature Request

Description

The post-install script in terra-i18n is deprecated. Users should switch to the terra-toolkit aggregate-translations pre-build tool.

Additional Context / Screenshots

Removing this will be a major version bump to terra-i18n

We've removed this once and it caused breaking issues with some of our consumers, namely around Jest testing. We'll want to document how to test with Jest once we no longer write files via post-install lifecycle hook.

@emilyrohrbough had good ideas around looking into running aggregate-translations pre-build tool in Jest setup and providing a terra Jest config to resolve the files generated from the aggregate-translations pre-build tool

[bjankord]

This has been resolved in terra-base@5.0.0/terra-i18n@4.0.0.
If consumers run into issues with Jest tests, they should consult our recommendations on testing terra components that have translations with Jest here.