Restful refactor of accounts/ routes (#2133)

* Add routing specs for accounts followers and following actions

* Use more restful route naming for public account follow pages

Moves two actions:
- accounts#followers to accounts/follower_accounts#index
- accounts#following to accounts/following_accounts#index

Adds routing spec to ensure prior URLs are preserved.

app/controllers/account_unfollow_controller.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class AccountUnfollowController < ApplicationController
+  include AccountControllerConcern
+
+  before_action :authenticate_user!
+
+  def create
+    UnfollowService.new.call(current_user.account, @account)
+    redirect_to account_path(@account)
+  end
+end