Docs: Add how to disable id/anon ID storage to docs

There seems to be confusion about the anonId and how to not persisting user data. We should add to the docs somewhere that if you're using the Analytics Core library, no IDs anonymous or otherwise are persisted.

E.g.

import { Analytics, EVENTS, CONSTANTS } from '@analytics/core'
import storage from '@analytics/storage-utils'

// See ../packages/analytics-core for source code
export default function analyticsLib(opts = {}) {
  // const defaultSettings = { storage } // no storage now
  return Analytics({
    ...defaultSettings,
    ...opts
  })
}

export { analyticsLib as init }
export { analyticsLib as Analytics }
export { EVENTS, CONSTANTS }

See more in https://github.com/DavidWells/analytics/issues/345

The docs live in https://github.com/DavidWells/analytics/tree/master/site/main/source dir. Maybe add a new file or update one where this might make sense

@claude

Start in site/main/source and review the existing Analytics Core documentation, then compare the behavior described here with the related issue 345. Add a clear explanation that Analytics Core persists no anonymous or other IDs when storage is not configured, and confirm the resulting documentation covers how to disable ID storage.