Give same behavior to InAppBrowser as CordovaWebView for self-signed certs

See CB-3576 for history. This is a request that came from there.

At least on the Android platform, the main webview (CordovaWebView) will silently accept self-signed certs when debuggable="true" in AndroidManifest.xml. (Hopefully other platforms have a similar behavior in pre-production.) The goal of this new feature is to get InAppBrowser to have the same behavior as the main webview in this respect, which is does not have today. Then both the main webview and InAppBrowser will behave consistently when they encounter https connections that have a self-signed cert.