Add Datadog APM agent [SCI-11842] (#8437)

Gemfile

@@ -96,6 +96,7 @@ gem 'js-routes'
 gem 'tailwindcss-rails', '~> 2.4'
 
 gem 'base62' # Used for smart annotations
+gem 'datadog'
 gem 'newrelic_rpm'
 
 # Permission helper Gem

Gemfile.lock

@@ -283,6 +283,13 @@ GEM
       activerecord (>= 5.a)
       database_cleaner-core (~> 2.0.0)
     database_cleaner-core (2.0.1)
+    datadog (2.14.0)
+      datadog-ruby_core_source (~> 3.4)
+      libdatadog (~> 16.0.1.1.0)
+      libddwaf (~> 1.21.0.0.1)
+      logger
+      msgpack
+    datadog-ruby_core_source (3.4.0)
     date (3.4.1)
     debug_inspector (1.1.0)
     deface (1.9.0)
@@ -408,6 +415,12 @@ GEM
       activerecord
       kaminari-core (= 1.2.2)
     kaminari-core (1.2.2)
+    libdatadog (16.0.1.1.0)
+    libdatadog (16.0.1.1.0-x86_64-linux)
+    libddwaf (1.21.0.0.1-arm64-darwin)
+      ffi (~> 1.0)
+    libddwaf (1.21.0.0.1-x86_64-linux)
+      ffi (~> 1.0)
     listen (3.8.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -415,6 +428,7 @@ GEM
     llhttp-ffi (0.4.0)
       ffi-compiler (~> 1.0)
       rake (~> 13.0)
+    logger (1.7.0)
     logging (2.0.0)
       little-plugger (~> 1.1)
       multi_json (~> 1.10)
@@ -795,6 +809,7 @@ DEPENDENCIES
   cssbundling-rails
   cucumber-rails
   database_cleaner
+  datadog
   deface (~> 1.9)
   delayed_job_active_record
   devise (~> 4.8.1)

config/application.rb

@@ -13,6 +13,7 @@ require 'action_mailer/railtie'
 require 'action_view/railtie'
 # require "action_cable/engine"
 # require "rails/test_unit/railtie"
+require 'datadog/auto_instrument' if ENV['DD_TRACE_ENABLED'] == 'true'
 
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.