refactor: move system information plugin to npm

[kieckhafer]

Impact: minor
Type: refactor

This PR removes the system-info plugin code from the API, and installs the @reactioncommerce/plugin-system-information to perform the same functions.

Breaking changes

None

Testing

The system information code is the same as it was before, it's just being installed from a different place, so you should see nothing different in the behavior of this PR and the v3.1.0 release it was created from.

1. Start the API
2. Create a user
3. Create a shop
4. Use the systemInformation GraphQL query to query system information

{
systemInformation(shopId: "SHOP_ID") {
  plugins {
    version
    name
  }
  apiVersion
  mongoVersion {
    version
  }
}
}

1. See system information

[willopez]

Everything looks good, just a minor comment.

[kieckhafer]

@willopez comment addressed

[willopez]

LGTM 👍