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/kotlin/com/simplemobiletools/smsmessenger/activities/ThreadActivity.kt

@@ -1602,6 +1602,7 @@ class ThreadActivity : SimpleActivity() {
             status = STATUS_NONE,
             participants = participants,
             date = (scheduledDateTime.millis / 1000).toInt(),
+            dateSent = (scheduledDateTime.millis / 1000).toInt(),
             read = false,
             threadId = threadId,
             isMMS = isMmsMessage(text),