Add support for parsing IETF RateLimit Headers draft 8 & 9

[nfriedly]

Draft 8 saw some significant updates; draft 9 may not need any additional work to support.

Draft 8: https://datatracker.ietf.org/doc/html/draft-ietf-httpapi-ratelimit-headers-08

Draft 9: https://datatracker.ietf.org/doc/html/draft-ietf-httpapi-ratelimit-headers-09

Summary of changes since draft 7: https://datatracker.ietf.org/doc/html/draft-ietf-httpapi-ratelimit-headers-09#name-since-draft-ietf-httpapi-ra

• Added Problem Types
• Clarified when to use RateLimit-Policy vs RateLimit fields

&

• Refactored both fields to lists of Items that identify policy and use parameters
• Added quota unit parameter
• Added partition key parameter

[gamemaker1]

Hi,

Sorry for the late reply. I took a look at the draft, and I'll try implementing it sometime this week.

[nfriedly]

Oh, cool! I've read part of the draft, but I haven't finished it yet.

[nfriedly]

🤦 This is the parser ticket. I moved the previous contents of this comment over to express-rate-limit/express-rate-limit#484 (comment) because they pertain more to generating headers than parsing them.