mod_http_oauth2: Strip trailing '/' from issuer URL

mod_http_oauth2: Advertise endpoints that are enabled If you don't set the registration secret, some of these are not actually available, so don't advertise them.

mod_http_oauth2: Separate client_secret verification key from JWT key Allows configuring a real JWT key directly in the config, but the client_secret will be different per host.

mod_http_oauth2: Fix response type config Wrong variable names

mod_http_oauth2/README: Document config options

mod_http_oauth2: Remove error message For a while I considered making this a required option but changed my mind and forgot to edit this.

mod_http_oauth2: Mention name of client when giving out OOB authorization code

mod_http_oauth2: Comment on mutation by other module

mod_http_oauth2: Implement stateless dynamic client registration Replaces previous explicit registration that required either the additional module mod_adhoc_oauth2_client or manually editing the database. That method was enough to have something to test with, but would not probably not scale easily. Dynamic client registration allows creating clients on the fly, which may be even easier in theory. In order to not allow basically unauthenticated writes to the database, we implement a stateless model here. per_host_key := HMAC(config -> oauth2_registration_key, hostname) client_id := JWT { client metadata } signed with per_host_key client_secret := HMAC(per_host_key, client_id) This should ensure everything we need to know is part of the client_id, allowing redirects etc to be validated, and the client_secret can be validated with only the client_id and the per_host_key. A nonce injected into the client_id JWT should ensure nobody can submit the same client metadata and retrieve the same client_secret

mod_http_oauth2: Add support for 'iss' authz response parameter (RFC 9207)