Show 2 checks when sms is delivered

- differentiate between sent sms and delivered sms by updating the SmsStatusSentReceiver which updates the type to Telephony.Sms.MESSAGE_TYPE_SENT or Telephony.Sms.MESSAGE_TYPE_FAILED depending on the outcome.
- rename ThreadSuccess to ThreadSent and add a boolean field for the delivery status
- SmsStatusSentReceiver updates the status of the message to Telephony.Sms.STATUS_COMPLETE.
- accommodate for the need to keep track of the status by adding Int field status to the Message class,
- add appropriate database migrations (3 to 4) for the new status field.
- add status to the query for sms in extension function Context.getMessages and Context.getMMS
- add extension function Context.updateMessageStatus to update the status of a message in the database

app/src/main/kotlin/com/simplemobiletools/smsmessenger/models/ThreadSent.kt

@@ -0,0 +1,5 @@
+package com.simplemobiletools.smsmessenger.models
+
+// show a check after the latest message, if it is a sent one and succeeded,
+// show a double check if it is delivered
+data class ThreadSent(val messageID: Long, val delivered: Boolean) : ThreadItem()