feat(servicecatalog): Add new check servicecatalog_portfolio_shared_within_organization_only

[MarioRgzLpz]

Context

Added a new check within the Service Catalog framework to ensures that portfolios are shared only within an AWS Organization if Organizations is enabled. The control will fail if a portfolio is being shared with an account while Organizations is active.

Description

Added check servicecatalog_portfolio_shared_within_organization_only with respective unit tests and metadata.

Checklist

• Are there new checks included in this PR? Yes
  • If so, do we need to update permissions for the provider? No.
• Review if the code is being covered by tests.
• Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings
• Review if backport is needed.

License

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

[codecov]

Codecov Report

Attention: Patch coverage is 93.75000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 89.91%. Comparing base (a2dba30) to head (0a41bf1).
Report is 27 commits behind head on master.

Files with missing lines	Patch %	Lines
.../services/servicecatalog/servicecatalog_service.py	75.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5632      +/-   ##
==========================================
+ Coverage   89.84%   89.91%   +0.06%     
==========================================
  Files        1118     1124       +6     
  Lines       34664    34812     +148     
==========================================
+ Hits        31144    31301     +157     
+ Misses       3520     3511       -9     

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