Add message details menu button

Adds a "Properties" menu button in conversation, when one message
is selected, which displays details about the message:
- Type (SMS or MMS)
- Sender phone number (or receiver if it is a sent message)
- Used SIM
- Date sent at
- Date received at (if it is an incoming message)

This closes #19

app/src/main/res/layout/dialog_message_details.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.simplemobiletools.commons.views.MyTextView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/dialog_message_details_text_value"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:paddingStart="@dimen/big_margin"
+    android:paddingTop="@dimen/big_margin"
+    android:paddingEnd="@dimen/big_margin"
+    android:textIsSelectable="true"
+    android:textSize="@dimen/big_text_size"
+    tools:text="My sample text" />