Remove site search functionality

This hasn't been used since the 3-in-1 migration occurred yet we still
get lots of spammy traffic to this endpoint. We can remove this and kill
off the legacy Algolia instance(s) that support it.

Gemfile

@@ -36,7 +36,6 @@ gem 'activerecord-session_store'
 # this repo, as all the gem is doing is wrapping OpenSSL.
 ##############################################################
 gem 'aes', github: 'chicks/aes'
-gem 'algoliasearch'
 gem 'attr_encrypted', '~> 3.1'
 gem 'blind_index', '0.2.0'
 gem 'delayed_job_active_record'
@@ -80,7 +79,6 @@ gem 'adal', github: 'moneyadviceservice/azure-activedirectory-library-for-ruby'
 gem 'cream', '2.1.8'
 gem 'dough-ruby', github: 'moneyadviceservice/dough', branch: 'PostMessages_v5.45'
 gem 'mas-cms-client', '1.20.1'
-gem 'site_search', '0.3.0'
 # Tools
 gem 'action_plans', github: 'moneyadviceservice/action_plans', ref: 'edb52f8'
 gem 'advice_plans', '~> 4.1.1'

Gemfile.lock

@@ -235,9 +235,6 @@ GEM
       rails (>= 4, < 5)
       recaptcha
       sass-rails
-    algoliasearch (1.19.2)
-      httpclient (~> 2.8, >= 2.8.3)
-      json (>= 1.5.1)
     angularjs-rails (1.2.26)
     arel (6.0.4)
     ast (2.4.0)
@@ -450,7 +447,6 @@ GEM
     http-accept (1.7.0)
     http-cookie (1.0.4)
       domain_name (~> 0.5)
-    httpclient (2.8.3)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
     i18n-js (3.0.0.mas)
@@ -732,8 +728,6 @@ GEM
     site_prism (2.11)
       addressable (~> 2.4)
       capybara (~> 2.7)
-    site_search (0.3.0)
-      algoliasearch
     spreadsheet (1.2.8)
       ruby-ole
     sprockets (2.12.5)
@@ -811,7 +805,6 @@ DEPENDENCIES
   advice_plans (~> 4.1.1)
   aes!
   agreements (~> 2.5.0)
-  algoliasearch
   attr_encrypted (~> 3.1)
   autoprefixer-rails
   better_errors
@@ -902,7 +895,6 @@ DEPENDENCIES
   selenium-webdriver
   shoulda-matchers
   site_prism
-  site_search (= 0.3.0)
   statsd-ruby
   sucker_punch
   syslog-logger

app/controllers/application_controller.rb

@@ -48,12 +48,6 @@ def covid_banner_dismissed?
 
   helper_method :covid_banner_dismissed?
 
-  def display_search_box_in_header?
-    true
-  end
-
-  helper_method :display_search_box_in_header?
-
   def contact_panels_border_top?
     false
   end

app/controllers/styleguide_controller.rb

@@ -23,10 +23,6 @@ def contact_panels_border_top?
     render layout: 'styleguide/page_unconstrained'
   end
 
-  def pages_search_results
-    render layout: 'styleguide/page'
-  end
-
   def pages_parent_category_page
     render layout: 'styleguide/page'
   end