Better Documentation in Code for Cardinal Care

[harshitgupta412]

• Add comments to the code (explain what each function is doing and relevant conditions)
• Link External Sources used
• Explain the schema

[labhinav]

Add links to all data sources @harshitgupta412

[labhinav]

Add descriptions for all test cases - if not covered - then why?

[labhinav]

add explanations in schema.txt

[labhinav]

in schema.txt - vaccine_dose_count_annual needs explanation