Mark plugin-/engine-Tags as deprecated

[GitToTheHub]

Bug Report

On a conversation on slack it turned out, that plugin-Tags and engine-Tags are deprecated to use in config.xml. It should be clear for the user, that these tags are deprecated and they should be only maintained by the package.json-File.

Problem

There is no hint, that these tags are deprecated. The documentation don't say anything, nor the cli.
Some old users could still use the plugin- and engine-Tags in the config.xml and could be wondered what is the right way.

What is expected to happen?

There should be somewhere a hint, that these tags are deprecated.

What does actually happen?

There is nowhere a hint, that these tags are deprecated.

Checklist

• I searched for existing GitHub issues
• I updated all Cordova tooling to most recent version
• I included all the necessary information above