Work for TS 54 (Round 5)

[reshmabidikar]

Final round of work. Includes the following:

• Moved the complex payment-related reports from src/main/resources/reports directory to the top-level reports directory
• Check for inconsistencies between thesrc/main/resources/reports/README.md updated the top-level Readme accordingly.
• Additional reports from AWS
• Improvements to README

Some notes:

• The churn related queries were very slow, so I had to add some additional indices to some analytics and some KB tables. See churn-indices.ddl
• I was not able to get the queries used in the payment_provider_conversion reports to work. For now, I've copied these over as they are, without including any report screenshots.