Feature: Installation global config (#839) (#840)

* Renamed concern from Feature to Featurable

* Feature: Installation config (#839)
* Added new model installtion config with corresponding migrations and specs
* Created an installation config yml (key value store model)
* Created a config loader module to load the installaltion configs
* Added this to the config loader seeder
* Changed the account before create hook for default feature enabling to use the feature values from installtion config
* Renamed the feature concern to Featurable to follow the naming pattern for concerns
* Added comments and specs for modules and places that deemed necessary

* Refactored config loader to reduce cognitive complexity (#839)

app/models/installation_config.rb

@@ -0,0 +1,31 @@
+# == Schema Information
+#
+# Table name: installation_configs
+#
+#  id               :bigint           not null, primary key
+#  name             :string           not null
+#  serialized_value :jsonb            not null
+#  created_at       :datetime         not null
+#  updated_at       :datetime         not null
+#
+# Indexes
+#
+#  index_installation_configs_on_name_and_created_at  (name,created_at) UNIQUE
+#
+class InstallationConfig < ApplicationRecord
+  serialize :serialized_value, HashWithIndifferentAccess
+
+  validates :name, presence: true
+
+  default_scope { order(created_at: :desc) }
+
+  def value
+    serialized_value[:value]
+  end
+
+  def value=(value_to_assigned)
+    self.serialized_value = {
+      value: value_to_assigned
+    }.with_indifferent_access
+  end
+end