FIX: Ensure CORS rules exist for S3 using rake task (#14802)

This commit introduces a new s3:ensure_cors_rules rake task
that is run as a prerequisite to s3:upload_assets. This rake
task calls out to the S3CorsRulesets class to ensure that
the 3 relevant sets of CORS rules are applied, depending on
site settings:

* assets
* direct S3 backups
* direct S3 uploads

This works for both Global S3 settings and Database S3 settings
(the latter set directly via SiteSetting).

As it is, only one rule can be applied, which is generally
the assets rule as it is called first. This commit changes
the ensure_cors! method to be able to apply new rules as
well as the existing ones.

This commit also slightly changes the existing rules to cover
direct S3 uploads via uppy, especially multipart, which requires
some more headers.

app/controllers/uploads_controller.rb

@@ -224,22 +224,15 @@ class UploadsController < ApplicationController
       )
     end
 
-    metadata = parse_allowed_metadata(params[:metadata])
-
-    url = Discourse.store.signed_url_for_temporary_upload(
-      file_name, metadata: metadata
-    )
-    key = Discourse.store.path_from_url(url)
-
-    upload_stub = ExternalUploadStub.create!(
-      key: key,
-      created_by: current_user,
-      original_filename: file_name,
+    external_upload_data = ExternalUploadManager.create_direct_upload(
+      current_user: current_user,
+      file_name: file_name,
+      file_size: file_size,
       upload_type: type,
-      filesize: file_size
+      metadata: parse_allowed_metadata(params[:metadata])
     )
 
-    render json: { url: url, key: key, unique_identifier: upload_stub.unique_identifier }
+    render json: external_upload_data
   end
 
   def complete_external_upload
@@ -307,7 +300,6 @@ class UploadsController < ApplicationController
     file_name = params.require(:file_name)
     file_size = params.require(:file_size).to_i
     upload_type = params.require(:upload_type)
-    content_type = MiniMime.lookup_by_filename(file_name)&.content_type
 
     if file_size_too_big?(file_name, file_size)
       return render_json_error(
@@ -316,11 +308,13 @@ class UploadsController < ApplicationController
       )
     end
 
-    metadata = parse_allowed_metadata(params[:metadata])
-
     begin
-      multipart_upload = Discourse.store.create_multipart(
-        file_name, content_type, metadata: metadata
+      external_upload_data = ExternalUploadManager.create_direct_multipart_upload(
+        current_user: current_user,
+        file_name: file_name,
+        file_size: file_size,
+        upload_type: upload_type,
+        metadata: parse_allowed_metadata(params[:metadata])
       )
     rescue Aws::S3::Errors::ServiceError => err
       return render_json_error(
@@ -329,21 +323,7 @@ class UploadsController < ApplicationController
       )
     end
 
-    upload_stub = ExternalUploadStub.create!(
-      key: multipart_upload[:key],
-      created_by: current_user,
-      original_filename: file_name,
-      upload_type: upload_type,
-      external_upload_identifier: multipart_upload[:upload_id],
-      multipart: true,
-      filesize: file_size
-    )
-
-    render json: {
-      external_upload_identifier: upload_stub.external_upload_identifier,
-      key: upload_stub.key,
-      unique_identifier: upload_stub.unique_identifier
-    }
+    render json: external_upload_data
   end
 
   def batch_presign_multipart_parts