1. Added files for AWS GuardDuty UDI Connector module
2. Added the following files related to PR opencybersecurityalliance#1516  to avoid CI failures.
   1. json_to_stix_translator.py
   2. gcp chronicle Read me, to-stix and unit test case files
   3.  Reaqta unit test case file.
3.  Updated stix_shifter.py file for handling serialization failure of datetime.datetime object.

Updated file with detailed description for Detector Ids

1. Removed Cybox attribute from the to-stix file.
2. Updated supported Stix mappings.

Updated the mapping files, unit test cases, read me and supported stix files by modifying account id and region related details to x-aws-resource.

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