Rename E2E template init script, relocate Verdaccio config + storage (#43001)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/43001

More understandable name: ~"React Native init, for E2E testing". Also relocates Verdaccio config and storage location under `scripts/e2e/` (resolving TODO comment).

The intent is for the `scripts/e2e/` dir to also group the existing E2E testing-related scripts — although I will stop here for the current release-related work.

Changelog: [Internal]

Reviewed By: lunaleaps

Differential Revision: D53609332

fbshipit-source-id: fb2f6502a18c4a4ac2368b46af1e3ee42edbadd6