Log image and message sends

Each WhatsApp send logs one line, message sent at info or message send
failed at warning with its safe cause, and an image shown in Telegram
logs image sent. A chat shows as a short hash, the same for received
images and sends, so the log tells chats apart with no phone number,
text, or caption. Before, a successful send left no trace in the
journal.

Issue: 441b3c7