Organize project files

Put QML components into folders, remove unused ones, split __init__.py
with engine.py.

harmonyqml/components/chat/Daybreak.qml

@@ -0,0 +1,12 @@
+import QtQuick 2.7
+import "../base" as Base
+
+Base.HLabel {
+    text: date_time.toLocaleDateString()
+    width: rootCol.width
+    horizontalAlignment: Text.AlignHCenter
+    topPadding: rootCol.isFirstMessage ? 0 : rootCol.verticalPadding * 4
+    bottomPadding: rootCol.verticalPadding * 2
+    font.pixelSize: normalSize * 1.1
+    color: "darkolivegreen"
+}