- Refactoring of the mail sending part. Mail queue (table 'queued') is now used also for all test emails.

- More options how to send test emails.
- Fixed problems with pausing a campaign (#593)
- Started rework of transactional sender of templates (#606), however this contains functionality regression at the moment because it does not interpret templates as HBS. It needs HBS option for templates as described in https://github.com/Mailtrain-org/mailtrain/issues/611#issuecomment-502345227

TODO:
- detect sending errors connected to not able to contact the mailer and pause/retry campaing and queued sending - don't mark the recipients as BOUNCED
- add FAILED campaign state and fall into it if sending to campaign consistently fails (i.e. the error with sending is not temporary)
- if the same happends for queued email, delete the message

server/routes/rest/campaigns.js

@@ -114,6 +114,12 @@ router.postAsync('/campaigns-link-clicks-table/:campaignId', passport.loggedIn,
     return res.json(await campaigns.listLinkClicksDTAjax(req.context, castToInteger(req.params.campaignId), req.body));
 });
 
+router.postAsync('/campaign-test-send', passport.loggedIn, passport.csrfProtection, async (req, res) => {
+    const data = req.body;
+    const result = await campaigns.testSend(req.context, data);
+    return res.json(result);
+});
+
 
 
 module.exports = router;