sift-sdk-web: React Hooks support

Major Release

Features

• Support for building sifts end-to-end with React hooks, with a simple implementation. See #7 for full details.

Other

• Only publish build files, rather than every file in the repository.
• Replaced @redsift/rollup-bundler with the latest version of rollup
• Added prettier + eslint pre-commit configuration
• Deleted some unrequired files