Switch to yarn v1 (#8)

## Change description

This project was setup with yarn 3 (as is the default for new
react-native projects). Yarn 1 is still supported though, and in used by
most other company projects.

This PR enables version 1 for this project as well by calling `yarn set
version 1.22.22`.

It is also cleaning up the redundant `package-lock.json` that got
introduced in #7 but is not needed.

Changes in `yarn.lock` are mostly removing duplicates.

## Type of Change

- [ ] Bug fix      <!-- fixes an issue -->
- [ ] Feature      <!-- adds functionality -->
- [x] Enhancement  <!-- improves something existing -->

Author: stigi