Merge pull request #931 from edx/jarv/release-ami-update

updating ami for official release
Fix forum LISTEN_{HOST,PORT} env variable names
Updating var syntax.
Adding non-empty check.
Merge pull request #941 from IONISx/fix-forum-env-variables

Fix forum LISTEN_{HOST,PORT} env variable names
The jenkins_worker roles needs to include the role defaults.

These roles now set various default passwords that the edxlocal role
needs.
adding ENABLE_AUTO_AUTH
explicitly state aws_region var
Merge pull request #944 from edx/jarv/performance-test-sandbox

adding ENABLE_AUTO_AUTH
Merge pull request #945 from edx/han/sendlogstos3

explicitly state aws_region var
adding user provided extra vars
Merge pull request #946 from edx/jarv/performance-test-sandbox

adding user provided extra vars
fixing region variable
Merge pull request #947 from edx/han/sendlogstos3

fixing region variable
adding datadog tag to sandboxes
Update jenkins worker playbook to current requirements
Merge pull request #949 from edx/jarv/add-dd-monitored-tag

Jarv/add dd monitored tag
adding defaults for CC_PROCESSOR
Merge pull request #951 from edx/jarv/edxapp-cc

adding defaults for CC_PROCESSOR
Merge pull request #950 from edx/zoldak/update-jenkins-worker-playbook

Update jenkins worker playbook to current requirements