Remove OIDC from code (#5233)

* Reject OIDC design

Out of scope.

* Remove OIDC

* Remove OIDC APIs

* Remove OIDC + OAuth2 from code

* Restore removed lakectl

* [lint] Remove unused

* Restore OIDC token handling

Interpret OIDC claims that an _external_ auth service may set on the
browser.

* Restore OIDC auth to OpenAPI

api/swagger.yml

@@ -33,6 +33,7 @@ components:
       type: apiKey
       in: cookie
       name: oidc_auth_session
+
   parameters:
     PaginationPrefix:
       in: query
@@ -688,14 +689,6 @@ components:
           enum: [initialized, not_initialized, comm_prefs_done]
         login_config:
           $ref: "#/components/schemas/LoginConfig"
-        oidc_enabled:
-          deprecated: true
-          type: boolean
-          description: "Deprecated: embedded OIDC support is now deprecated"
-        oidc_default_login:
-          deprecated: true
-          type: boolean
-          description: "Deprecated: embedded OIDC support is now deprecated"
     AccessKeyCredentials:
       type: object
       properties:
@@ -1379,21 +1372,6 @@ paths:
               schema:
                 $ref: "#/components/schemas/CurrentUser"
 
-  /oidc/callback:
-    get:
-      deprecated: true
-      description: "Deprecated: embedded OIDC support is now deprecated"
-      tags:
-        - auth
-      operationId: oauthCallback
-      security: []
-      responses:
-        302:
-          description: successfully got token
-        401:
-          description: failed to exchange authorization code for token
-        default:
-          $ref: "#/components/responses/ServerError"
   /auth/login:
     post:
       tags: