i18n: add landing page translations (en/ru)

Added/updated translations for:
- howto: step labels
- stats: suppliers desc, countries
- testimonial: quote, author, role
- roles: subtitle, updated benefits
- cta: register, demo buttons
- footer: all countries, offices, products, services, legal

i18n/locales/en/roles.json

@@ -1,11 +1,12 @@
 {
   "roles": {
     "title": "Who Our Platform Is For",
+    "subtitle": "Platform for all agricultural commodity market participants",
     "producers": {
       "title": "Producers",
       "description": "Sell raw materials directly to buyers through our platform",
-      "benefit1": "Sales bulletin board",
-      "benefit2": "Auction tender participation",
+      "benefit1": "Direct access to buyers",
+      "benefit2": "Transparent pricing",
       "benefit3": "Access to financing",
       "benefit4": "Logistics solutions",
       "cta": "Start Selling"