[SYNCOPE-538] mailTemplates/ subdir externalized

git-svn-id: https://svn.apache.org/repos/asf/syncope/branches/1_2_X@1615559 13f79535-47bb-0310-9956-ffa450edef68
[SYNCOPE-138] Merge from 1_2_X

git-svn-id: https://svn.apache.org/repos/asf/syncope/trunk@1615560 13f79535-47bb-0310-9956-ffa450edef68