Refs #17503 Reimplementation of Validate emails using threads in backed

In this way the server is able to serve future clients requsts with
minimum interference.

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs@20538 a0171fae-0946-0410-966d-b1775066cd26
Email Validation - resolve validation in backend threads (avoid server load)

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs@20539 a0171fae-0946-0410-966d-b1775066cd26
release 1.4.28, new version 1.4.29

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs@20540 a0171fae-0946-0410-966d-b1775066cd26
release 1.2.49, new version 1.2.50

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs@20541 a0171fae-0946-0410-966d-b1775066cd26
release 1.2.49, new version 1.2.50

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs@20542 a0171fae-0946-0410-966d-b1775066cd26
release 1.4.28, new version 1.4.29

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs@20543 a0171fae-0946-0410-966d-b1775066cd26
release 3.3.23, new version 3.3.24

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs@20544 a0171fae-0946-0410-966d-b1775066cd26