BN-41 | Add. i18n Support

[rahu1ramesh]

JIRA -> BN-41

This PR adds comprehensive internationalization (i18n) functionality to the Bahmni Clinical Frontend application, enabling multi-language support with a robust translation management system.

Key Features

• Dual-Source Translation Strategy: Fetches translations from both bundled files and configuration sources
• Asynchronous Loading: Loads translations asynchronously during application startup
• User Locale Detection: Automatically detects and applies the user's preferred language
• Fallback Mechanism: Uses English as fallback when translations are missing
• Error Handling: Comprehensive error handling for missing or invalid translations

Implementation Details

• i18n Core Setup: Configures i18next with React bindings and browser language detection
  Translation Service:
• getUserPreferredLocale(): Retrieves user's language preference from localStorage
• getTranslations(): Fetches and merges translations from bundled and config sources
• getMergedTranslations(): Handles merging with config translations taking precedence
• TranslationProvider: Provides React Suspense-based loading state while translations are being fetched

Constants & Configuration:

• URL templates for both bundled and config translation sources
• Default locale and namespace settings
• Cookie/localStorage configuration
• Testing & Type Definitions: Includes comprehensive unit tests, integration tests, and TypeScript type definitions

NOTE: No new translation keys have been introduced, except in cases where a corresponding key does not already exist in the existing Bahmni Apps i18n locale files.
NOTE: The i18n implementation expects at least the english translation key file to be present either bundled or at the configuration source, without which the frontend will throw an error.