Add an ability to initialize SDK using specific AD UNIT

[AGulev]

extension-ironsource/extension-ironsource/src/java/com/defold/ironsource/IronSourceJNI.java

Line 67 in d93a3fc

//TODO: add AD Units android.app.Activity, java.lang.String, com.ironsource.mediationsdk.sdk.InitializationListener, com.ironsource.mediationsdk.IronSource$AD_UNIT...

//Rewarded Video
IronSource.init(this, appKey, IronSource.AD_UNIT.REWARDED_VIDEO);
//Init Interstitial 
IronSource.init(this, appKey, IronSource.AD_UNIT.INTERSTITIAL); 
//Init Offerwall
IronSource.init(this, appKey, IronSource.AD_UNIT.OFFERWALL) 
//Init Banner
IronSource.init(this, appKey, IronSource.AD_UNIT.BANNER);

/**
*Ad Units should be in the type of IronSource.Ad_Unit.AdUnitName, example 
*/
IronSource.init(this, appKey, IronSource.AD_UNIT.OFFERWALL, IronSource.AD_UNIT.INTERSTITIAL, IronSource.AD_UNIT.REWARDED_VIDEO, IronSource.AD_UNIT.BANNER);

https://developers.is.com/ironsource-mobile/android/android-sdk/#step-5