fix: Relates to #124. Security (#451)

* feat: Security aspects for fether-electron. See #124

* feat: Add Source Maps support

* docs: Add Source Maps guide to Readme

* feat: Add webpack-build-notifier add-on with custom Webpack config

* fix: Remove duplicate dependency

* WIP

* WIP

* review-fix: Configure CSP depending on NODE_ENV

* fix: Fix worker-src for the camera in production

* review-fix: Remove unnecessary config of source maps dependency

* Use preload script as buffer between main and renderer processes (#463)

* fix: Remove is-electron since now using preload script

* fix: Remove old preload script

* fix: Do not expose electron, remote, or require to web app

* fix: Add newline

* feat: Single Fether instance lock

* fix: Move preload to static folder so works with binary

* review-fix: Remove fix for webview since not used. Add comment incase used in future. Fix other event handling code

* review-fix: Add optional opt-in to using Webpack notifier pl...