convert MainActivity to Kotlin and upgrade MaterialDrawer to version 8 (#1748)

* convert MainActivity to Kotlin

* migrate to MaterialDrawer 8

* fix drawer styles

* revert removing BezelImageView and material_drawer_header override

* fix tests

* add lost comment back to material_drawer_header.xml

* add tools:parentTag to material_drawer_header.xml

* use when instead of if in MainActivity

* fix statusbar color over the drawer

* cleanup drawer item creation

* tint secondary drawer items as well

* remove unnecessary ids

* fix header text color in the light theme

* improve header text contrast

app/src/main/java/com/keylesspalace/tusky/view/BezelImageView.java

@@ -21,7 +21,6 @@ import android.util.AttributeSet;
 import android.view.View;
 import android.view.ViewOutlineProvider;
 
-
 /**
  * override BezelImageView from MaterialDrawer library to provide custom outline
  */
@@ -39,7 +38,6 @@ public class BezelImageView extends com.mikepenz.materialdrawer.view.BezelImageV
         super(context, attrs, defStyle);
     }
 
-
     @Override
     protected void onSizeChanged(int w, int h, int old_w, int old_h) {
         setOutlineProvider(new CustomOutline(w, h));