[TIMOB-27857] Webpack: Add support for plugins from NPM

*Use case* The plugin api in appcd-plugin-webpack currently only supports local plugins via the appcdWebpackPlugins property in package.json. To easily share plugins installing them via NPM should be supported as well. *Plugin naming convention* For plugins to be discoverable they must follow a specific naming convention: * appcd-webpack-plugin-<name> * @scope/appcd-webpack-plugin-<name> Plugins that are maintained by us can make use of the official scopes @appcd and @titanium-sdk and drop the leading appcd- prefix. * @appcd/webpack-plugin-<name> * @titanium-sdk/webpack-plugin-<name> *Plugin API changes* The [hasPlugin](https://github.com/appcelerator/appcd-plugin-webpack/blob/dab4ffcc36df7491da3ad4337e0b1114938fbc0c/src/plugin-api/plugin-api.js#L93) methods needs to allow for easy matching of plugin names. Instead of requiring the full package name a short hand check should be available as well. * <name> to check for appcd-webpack-plugin-<name> * @scope/<name> to check for @scope/appcd-webpack-plugin-<name>