feat: add PKCE support for OAuth2 Authorization Code flows (#5361)

* Add PKCE support.

* Fix tests

* Update oauth2.md

* Rename usePkce

* Fix the BrokenComponent error

* Update oauth2.md

* Remove isCode variable. Remove uuid4 dependency.

* Remove utils functions

* Import crypto

* Fix tests

* Fix the tests

* Cleanup

* Fix code_challenge generation

* Move code challenge and verifier to utils for mocks. Update tests.

* Mock the PKCE methods in the utils file properly.

* Add missing expect

* use target-method spies

* Add comments to explain test values.

* Get rid of jsrsasign.

docker/configurator/oauth.js

@@ -1,7 +1,7 @@
 const translator = require("./translator")
 const indent = require("./helpers").indent
 
-const  oauthBlockSchema = {
+const oauthBlockSchema = {
   OAUTH_CLIENT_ID: {
     type: "string",
     name: "clientId"
@@ -26,6 +26,10 @@ const  oauthBlockSchema = {
   OAUTH_ADDITIONAL_PARAMS: {
     type: "object",
     name: "additionalQueryStringParams"
+  },
+  OAUTH_USE_PKCE: {
+    type: "boolean",
+    name: "usePkceWithAuthorizationCodeGrant"
   }
 }