All - Change "iso29115" parameter to "ac" and reserve values "0", "1", "2", "3", "4"

[Michael Jones]

The "ac" claim is an Authentication Context Class Ref. The values "1", "2", "3", "4" are reserved for ISO 29115 definitions. The value "0" is reserved to be used in a manner equivalent to the current PAPE level 0.

[Nat Sakimura]

Re #494 - Messages. Defined Authn Context Class Ref and changed the iso29115 def.

Variable Name iso29115 is not yet changed. Note: It must not be mechanically replaced as it will break the reference.

→ 07b1addee43c

[Nat Sakimura]

I would propose acr instead of ac.

It will make the search easier as well as makes it in-line with the three letter param names in JWT. There is currently no string "acr" in any but one in Session as "across", so it will be an easy search. If it is ac, it is virtually impossible to search.

[Nat Sakimura]

Fixed in 915f449c1c1c

[John Bradley]

re #494 fix examples for acr and clarify null value response for optional claim.

→ 9463861d8659

[John Bradley]

re #494 fix examples for acr make paramater values

→ b0d7d67e7454

[John Bradley]

re #494 clean up description of acr_supported and example

→ e5e8c7eff55b

[John Bradley]

re #494 add reference to the IANA LoA registry

→ fc3ac58921c2