[JENKINS-20908] - Use Mailer plugin instead of internal FastMailResolver implementation
Resolves https://issues.jenkins-ci.org/browse/JENKINS-20908

Signed-off-by: Oleg Nenashev <nenashev@synopsys.com>
Merge pull request #18 from synopsys-arc-oss/fastMailResolver

[JENKINS-20908] - Use Mailer plugin instead of internal FastMailResolver implementation