build: Upload source maps to Sentry via Webpack plugin

Created by: plibither8

This PR adds the SentryWebpackPlugin through which we will upload source maps of the generated frontend scripts and send them to Sentry.

As a next step (in a separate PR), we will exclusively run this plugin during the release branch builds.

Test plan

Tested the success through a dry run, and altering the yarn build script to add RELEASE_CANDIDATE_VERSION, SENTRY_UPLOAD_SOURCE_MAPS and SENTRY_AUTH_TOKEN env vars.

App preview:

• Web
• Storybook

Check out the client app preview documentation to learn more.