Add country_code attribute to Security model and related classes

* Update Security model to include country_code in the data definition.
* Modify Provider::SecurityConcept to define country_code for security.
* Enhance Provider::Synth to extract country_code from security data.
* Update Security::Provided to include country_code when creating security instances.
* Adjust Security::SynthComboboxOption to add country_code as an attribute.
* Revise combobox_security partial to conditionally display country flag and code.

app/models/security.rb

@@ -21,6 +21,7 @@ class Security < ApplicationRecord
       name: name,
       logo_url: logo_url,
       exchange_operating_mic: exchange_operating_mic,
+      country_code: country_code
     )
   end