Support for import/export of instance-level domain blocks/allows for 4.x w/ additional fixes (#20597)

* Allow import/export of instance-level domain blocks/allows (#1754)

* Allow import/export of instance-level domain blocks/allows.
Fixes #15095

* Pacify circleci

* Address simple code review feedback

* Add headers to exported CSV

* Extract common import/export functionality to
AdminExportControllerConcern

* Add additional fields to instance-blocked domain export

* Address review feedback

* Split instance domain block/allow import/export into separate pages/controllers

* Address code review feedback

* Pacify DeepSource

* Work around Paperclip::HasAttachmentFile for Rails 6

* Fix deprecated API warning in export tests

* Remove after_commit workaround

(cherry picked from commit 94e98864e3)

* Add confirmation page when importing blocked domains (#1773)

* Move glitch-soc-specific strings to glitch-soc-specific locale files

* Add confirmation page when importing blocked domains

(cherry picked from commit b91196f4b7)

* Fix authorization check in domain blocks controller

(cherry picked from commit 7527937758)

* Fix error strings for domain blocks and email-domain blocks

Corrected issue with non-error message used for Mastodon:NotPermittedError in Domain Blocks
Corrected issue Domain Blocks using the Email Domain Blocks message on ActionContoller::ParameterMissing
Corrected issue with Email Domain Blocks using the not_permitted string from "custom emojii's"

* Ran i18n-tasks normalize to address test failure

* Removed unused admin.export_domain_blocks.not_permitted string

Removing unused string as indicated by Check i18n

* Fix tests

(cherry picked from commit 9094c2f52c)

* Fix domain block export not exporting blocks with only media rejection

(cherry picked from commit 26ff48ee48)

* Fix various issues with domain block import

- stop using Paperclip for processing domain allow/block imports
- stop leaving temporary files
- better error handling
- assume CSV files are UTF-8-encoded

(cherry picked from commit cad824d8f501b95377e4f0a957e5a00d517a1902)

Co-authored-by: Levi Bard <taktaktaktaktaktaktaktaktaktak@gmail.com>
Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/controllers/concerns/admin_export_controller_concern.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module AdminExportControllerConcern
+  extend ActiveSupport::Concern
+
+  private
+
+  def send_export_file
+    respond_to do |format|
+      format.csv { send_data export_data, filename: export_filename }
+    end
+  end
+
+  def export_data
+    raise 'Override in controller'
+  end
+
+  def export_filename
+    raise 'Override in controller'
+  end
+
+  def set_dummy_import!
+    @import = Admin::Import.new
+  end
+
+  def import_params
+    params.require(:admin_import).permit(:data)
+  end
+
+  def import_data_path
+    params[:admin_import][:data].path
+  end
+
+  def parse_import_data!(default_headers)
+    data = CSV.read(import_data_path, headers: true, encoding: 'UTF-8')
+    data = CSV.read(import_data_path, headers: default_headers, encoding: 'UTF-8') unless data.headers&.first&.strip&.include?(default_headers[0])
+    @data = data.reject(&:blank?)
+  end
+end