Add support for MFA with Duo's Universal Prompt (#4637)

* Add initial working Duo Universal Prompt support.

* Add db schema and models for Duo 2FA state storage

* store duo states in the database and validate during authentication

* cleanup & comments

* bump state/nonce length

* replace stray use of TimeDelta

* more cleanup

* bind Duo oauth flow to device id, drop redundant device type handling

* drop redundant alphanum string generation code

* error handling cleanup

* directly use JWT_VALIDITY_SECS constant instead of copying it to DuoClient instances

* remove redundant explicit returns, rustfmt

* rearrange constants, update comments, error message

* override charset on duo state column to ascii for mysql

* Reduce twofactor_duo_ctx state/nonce column size in postgres and maria

* Add fixes suggested by clippy

* rustfmt

* Update to use the make_http_request

* Don't handle OrganizationDuo

* move Duo API endpoint fmt strings out of macros and into format! calls

* Add missing indentation

Co-authored-by: Daniel García <dani-garcia@users.noreply.github.com>

* remove redundant expiry check when purging Duo contexts

---------

Co-authored-by: BlackDex <black.dex@gmail.com>
Co-authored-by: Daniel García <dani-garcia@users.noreply.github.com>

src/config.rs

@@ -415,7 +415,9 @@ make_config! {
         /// Auth Request cleanup schedule |> Cron schedule of the job that cleans old auth requests from the auth request.
         /// Defaults to every minute. Set blank to disable this job.
         auth_request_purge_schedule:   String, false,  def,    "30 * * * * *".to_string();
-
+        /// Duo Auth context cleanup schedule |> Cron schedule of the job that cleans expired Duo contexts from the database. Does nothing if Duo MFA is disabled or set to use the legacy iframe prompt.
+        /// Defaults to once every minute. Set blank to disable this job.
+        duo_context_purge_schedule:   String, false,  def,    "30 * * * * *".to_string();
     },
 
     /// General settings
@@ -635,6 +637,8 @@ make_config! {
     duo: _enable_duo {
         /// Enabled
         _enable_duo:            bool,   true,   def,     true;
+        /// Attempt to use deprecated iframe-based Traditional Prompt (Duo WebSDK 2)
+        duo_use_iframe:         bool,   false,  def,     false;
         /// Integration Key
         duo_ikey:               String, true,   option;
         /// Secret Key