Clean up generation of account webfinger string (#1477)

* Consolidate webfinger string creation under Account#to_webfinger_s

* Introduce Account#local_username_and_domain for consolidation

app/controllers/accounts_controller.rb

@@ -53,7 +53,7 @@ class AccountsController < ApplicationController
   end
 
   def webfinger_account_url
-    webfinger_url(resource: "acct:#{@account.acct}@#{Rails.configuration.x.local_domain}")
+    webfinger_url(resource: @account.to_webfinger_s)
   end
 
   def check_account_suspension

app/controllers/remote_follow_controller.rb

@@ -25,7 +25,7 @@ class RemoteFollowController < ApplicationController
 
       session[:remote_follow] = @remote_follow.acct
 
-      redirect_to Addressable::Template.new(redirect_url_link.template).expand(uri: "#{@account.username}@#{Rails.configuration.x.local_domain}").to_s
+      redirect_to Addressable::Template.new(redirect_url_link.template).expand(uri: @account.to_webfinger_s).to_s
     else
       render :new
     end

app/controllers/settings/exports_controller.rb

@@ -39,7 +39,7 @@ class Settings::ExportsController < ApplicationController
   def accounts_list_to_csv(list)
     CSV.generate do |csv|
       list.each do |account|
-        csv << [(account.local? ? "#{account.username}@#{Rails.configuration.x.local_domain}" : account.acct)]
+        csv << [(account.local? ? account.local_username_and_domain : account.acct)]
       end
     end
   end

app/controllers/xrd_controller.rb

@@ -14,7 +14,7 @@ class XrdController < ApplicationController
 
   def webfinger
     @account = Account.find_local!(username_from_resource)
-    @canonical_account_uri = "acct:#{@account.username}@#{Rails.configuration.x.local_domain}"
+    @canonical_account_uri = @account.to_webfinger_s
     @magic_key = pem_to_magic_key(@account.keypair.public_key)
 
     respond_to do |format|