Update {IANA Considerations} section

[richsalz]

Merge three "add to table" into one request to "add these to the table" Create a new registry for quota fields.

[richsalz]

looks good!

[ioggstream]

@unleashed @richsalz I made some edits:

• ad an addressable subsection for iana-ratelimit-parameters
• add parameters, description to iana table
• reference specification sections in IANA registries
• removed normative parts from IANA
• mention IANA table in {{quota-policy}}

Could you please PTAL?

[ioggstream]

looks good!

ooops I missed your comment :) Ok, let's merge.