Function to add an identifier code to API queries.
cqc_partner_code(check_env = FALSE)If TRUE, will check the environment variable
CQC_PARTNER_CODE first before asking for user input.
The CQC wants all organisations using this API to add an additional query identifying themselves to all queries.
If you are a CQC Syndication partner the value for this code
will be provided to you, otherwise an informative but concise code
representing your organisation should be chosen. The partner code can be set
as an environmental variable named CQC_PARTNER_CODE, or using this
function. If set, it will automatically be included in all queries.