Feature Request(Android): MediaStore API

Hi, I was using cordova-plugin-file, but now with scoped storage it is not practical if I want to allow the user to choose where they want to save the file.

The alternative is MediaStore API, however, https://github.com/Heartade/cordova-plugin-android-mediastore allows only saving a single image to the gallery and https://github.com/a-ferrari/com-thesis-cordova-plugins-pdfstore only a single PDF file.

This should be part of core functionality as many apps need to download files to a location selected by the user.

Begin by reviewing the Android MediaStore API and the two linked Cordova plugins, noting how they handle image and PDF storage under scoped storage. Done means core Cordova Android support enables apps to save multiple file types to a location selected by the user.

Written by the indexing model from the issue text.