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/test/java/com/keylesspalace/tusky/FilterTest.kt

@@ -115,7 +115,7 @@ class FilterTest {
 
 
         activity.supportFragmentManager.beginTransaction()
-                .replace(R.id.activity_main, fragment, "fragment")
+                .replace(R.id.mainDrawerLayout, fragment, "fragment")
                 .commit()
 
         fragment.reloadFilters(false)