Link account id with the external user store (#184)

* get account id from access token claim

* use GetOrCreateAccountByUser and add test

* correct account id claim

* remove unused account

* Idp manager interface

* auth0 idp manager

* use if instead of switch case

* remove unnecessary lock

* NewAuth0Manager

* move idpmanager to its own package

* update metadata when accountId is not supplied

* update tests with idpmanager field

* format

* new idp manager and config support

* validate if we fetch the interface before converting to string

* split getJWTToken

* improve tests

* proper json fields and handle defer body close

* fix ci lint notes

* documentation and proper defer position

* UpdateUserAppMetadata tests

* update documentation

* ManagerCredentials interface

* Marshal and Unmarshal functions

* fix tests

* ManagerHelper and ManagerHTTPClient

* further tests with mocking

* rename package and custom http client

* sync local packages

* remove idp suffix

management/server/testdata/management.json

@@ -33,5 +33,15 @@
         "AuthIssuer": "<PASTE YOUR AUTH0 ISSUER HERE>,",
         "AuthAudience": "<PASTE YOUR AUTH0 AUDIENCE HERE>",
         "AuthKeysLocation": "<PASTE YOUR AUTH0 PUBLIC JWT KEYS LOCATION HERE>"
+    },
+    "IdpManagerConfig": {
+        "Manager": "<none|auth0>",
+        "Auth0ClientCredentials": {
+            "Audience": "<PASTE YOUR AUTH0 AUDIENCE HERE>",
+            "AuthIssuer": "<PASTE YOUR AUTH0 Auth Issuer HERE>",
+            "ClientId": "<PASTE YOUR AUTH0 Application Client ID HERE>",
+            "ClientSecret": "<PASTE YOUR AUTH0 Application Client Secret HERE>",
+            "GrantType": "client_credentials"
+        }
     }
 }