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>

spec/fixtures/files/domain_allows.csv

@@ -0,0 +1,3 @@
+#domain
+good.domain
+better.domain

spec/fixtures/files/domain_blocks.csv

@@ -0,0 +1,4 @@
+#domain,#severity,#reject_media,#reject_reports,#public_comment,#obfuscate
+bad.domain,silence,false,false,bad,false
+worse.domain,suspend,true,true,worse,true
+reject.media,noop,true,false,reject media,false