migrate to multidatabase structure and clean up code

versions.gradle

@@ -3,6 +3,7 @@ ext.deps = [:]
 def versions = [:]
 versions.kotlin = "1.3.41"
 versions.gradle = "3.5.3"
+versions.room = "2.2.3"
 
 def deps = [:]
 
@@ -22,6 +23,11 @@ kotlin.version = "$versions.kotlin"
 kotlin.std_lib = "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$versions.kotlin"
 deps.kotlin = kotlin
 
+def room = [:]
+room.runtime = "androidx.room:room-runtime:$versions.room"
+room.compiler = "androidx.room:room-compiler:$versions.room"
+deps.room = room
+
 ext.deps = deps
 
 static def addRepos(RepositoryHandler handler) {