Updated readme.md

Added some short description for sql-assessment-api folder and described the json file Disabling...

Author: alexprotsenko

samples/manage/sql-assessment-api/README.md

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+# SQL Assessment API samples
+
+Contains samples for customizing SQL Assessment API. Learn more about API and how run it with your own customization here <link to the SQL Assessment docs page>.
+
+## DisablingBuiltInChecks_sample.json
+
+Contains two parts. First shows how you can disable a specified check by its name. The second disables all the checks with the "TraceFlag" tag.