Remove dependency on goldfinger gem (#14919)

There are edge cases where requests to certain hosts timeout when
using the vanilla HTTP.rb gem, which the goldfinger gem uses. Now
that we no longer need to support OStatus servers, webfinger logic
is so simple that there is no point encapsulating it in a gem, so
we can just use our own Request class. With that, we benefit from
more robust timeout code and IPv4/IPv6 resolution.

Fix #14091

app/models/account_alias.rb

@@ -33,7 +33,7 @@ class AccountAlias < ApplicationRecord
   def set_uri
     target_account = ResolveAccountService.new.call(acct)
     self.uri       = ActivityPub::TagManager.instance.uri_for(target_account) unless target_account.nil?
-  rescue Goldfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::Error
+  rescue Webfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::Error
     # Validation will take care of it
   end
 

app/models/account_migration.rb

@@ -54,7 +54,7 @@ class AccountMigration < ApplicationRecord
 
   def set_target_account
     self.target_account = ResolveAccountService.new.call(acct)
-  rescue Goldfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::Error
+  rescue Webfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::Error
     # Validation will take care of it
   end
 

app/models/form/redirect.rb

@@ -32,7 +32,7 @@ class Form::Redirect
 
   def set_target_account
     @target_account = ResolveAccountService.new.call(acct)
-  rescue Goldfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::Error
+  rescue Webfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::Error
     # Validation will take care of it
   end
 

app/models/remote_follow.rb

@@ -56,7 +56,7 @@ class RemoteFollow
 
     if domain.nil?
       @addressable_template = Addressable::Template.new("#{authorize_interaction_url}?uri={uri}")
-    elsif redirect_url_link.nil? || redirect_url_link.template.nil?
+    elsif redirect_uri_template.nil?
       missing_resource_error
     else
       @addressable_template = Addressable::Template.new(redirect_uri_template)
@@ -64,16 +64,12 @@ class RemoteFollow
   end
 
   def redirect_uri_template
-    redirect_url_link.template
-  end
-
-  def redirect_url_link
-    acct_resource&.link('http://ostatus.org/schema/1.0/subscribe')
+    acct_resource&.link('http://ostatus.org/schema/1.0/subscribe', 'template')
   end
 
   def acct_resource
     @acct_resource ||= webfinger!("acct:#{acct}")
-  rescue Goldfinger::Error, HTTP::ConnectionError
+  rescue Webfinger::Error, HTTP::ConnectionError
     nil
   end