How to embed Cordova in an existing Swift app

I think this documentation should be added somewhere around here (updated): https://cordova.apache.org/docs/en/latest/guide/platforms/ios/webview.html

with source here (updated): https://cordova.apache.org/docs/en/latest/guide/platforms/ios/webview.html

triggered by: https://github.com/apache/cordova/issues/177

also related: #875 - document Embed Cordova in native apps android webview ant jar deprecated

Review the existing iOS webview documentation at the linked Cordova page and the context from apache/cordova#177 and #875. Add guidance for embedding Cordova in an existing Swift app, with the relevant source placed around that page. Done means the documentation clearly explains the integration path for native Swift apps.

Written by the indexing model from the issue text.