docs(secure-payments): add standalone Secure Payment Pages docs and API reference, clarify support model, and simplify integration guidance#48

aimensahnoun wants to merge 1 commit intomainRequestNetwork/mintlify-docs:mainfrom

02-12-docs_secure-payments_add_standalone_secure_payment_pages_docs_and_api_reference_clarify_support_model_and_simplify_integration_guidanceRequestNetwork/mintlify-docs:02-12-docs_secure-payments_add_standalone_secure_payment_pages_docs_and_api_reference_clarify_support_model_and_simplify_integration_guidanceCopy head branch name to clipboard