[IONIC EXAMPLE] Added a Ionic example

Added a folder ionic-example with a Ionic 4 project that use this plugin. Please, see this if you have some doubt like use this plugin.

[Android/IOS] Start others apps

Inspired by cordova plugin startapp, this plugin starts an external app too.

This plugin contains more checks, like avoid that a same NativeView is opened more than once, and more directly and catch error messages from native to JS bridge. Now, this plugin decide if a external or the same app, depending which parameters you pass to NativeView.show() method.

[IOS] Fix missing custom Exception class

The class InstantiateViewControllerError was removed from src/ios folder, but the reference in plugin.xml wasn't. Fixed and publish to http://npmjs.org

Related issue: #13

[IOS] Use containsString() insteadof hasSuffix()

Verify the params StoryboardName and ViewControllerName that contains strings Controller or Storyboard in any part of the storyboard/class name.

[IOS] Refactor to instantiate Storyboards and ViewControllers

Merged refactors did in PR !12

[Android] Example/Jitpack project changed to Java

The android folder was changed from Kotlinproject to Java project. This avoid compilation errors when try use this plugin like a Jitpack dependency in any other Android project that not contains Kotlinsupport.

[Android] Added Jitpack support

Include this plugin like a gradle dependency with:

allprojects {
    repositories {
        ...
        maven { url 'https://jitpack.io' }
    }
}

implementation ('com.github.mfdeveloper:cordova-plugin-nativeview:0.0.4')

[Android] Improve exception errors + Promise support

Added Promise support to use this plugin + Android improvements to return Java exceptions to cordova app