build variants

# Feature Request: Build Variants

## Motivation Behind Feature

I would like the ability to create a development test version of my app. The dev version of the app should be able to be installed on devices alongside the latest release version. To allow this, I must change the app id to something unique. I also want to change the name to "appname-dev" to distinguish it from the release version on the user's app launcher.

Native Android has variants: https://developer.android.com/studio/build/build-variants

Native iOS has targets: https://developer.apple.com/library/archive/documentation/ToolsLanguages/Conceptual/Xcode_Overview/WorkingwithTargets.html

I searched and found some other people expressing similar interest:
https://stackoverflow.com/questions/35731142/build-variants-with-ionic-cordova
https://stackoverflow.com/questions/53521813/manage-multiple-build-variants-using-cordova-ionic-android-prject

## Feature Description

I want to be able to specify a build variant (or target?) on the CLI.
```
cordova build android --variant=dev
```
That would change the built app's widget id to "com.myco.appname_dev" and the name to "appname-dev".

To make this feature more general-purpose, perhaps the variants are defined in a file and each selects a separate config.xml.

## Alternatives or Workarounds

Currently I am editing config.xml by hand to change the id and name properties. But it is error-prone and tedious.
Also, each time I change the ID, it seems I have to remove and re-add the platforms to avoid build errors.

Start by tracing how the CLI handles `cordova build android` and how `config.xml` supplies the app ID and name. Compare the requested `--variant=dev` behavior with Android build variants and determine how variant-specific configuration would be selected; done means a development build can be installed beside the release build with the requested ID and name.

Written by the indexing model from the issue text.