Various fixes to API, IAM policies and tests

[demartinofra]

• add quotes to !Ref AWS::StackId in API template to handle template paring failures in some environments
• fix check for template url in cfn_stacks_factory. It needs to be an https url and not s3
• Add both ec2 service identifiers in PassRole policy - For some APIs such as AddRoleToInstanceProfile the PassedToService needs to be ec2.amazonaws.com also in China.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Merging #3157 (6a73fb0) into develop (0e16840) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #3157   +/-   ##
========================================
  Coverage    80.86%   80.86%           
========================================
  Files          160      160           
  Lines        12180    12180           
========================================
  Hits          9849     9849           
  Misses        2331     2331           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0e16840...6a73fb0. Read the comment docs.