Add Exness Server Integration for Account Connection

Implement Exness Server Support for Broker Account Connectivity

Users need the ability to connect their Exness trading accounts to PF1, but Exness is currently not available as a server option in the account connection interface. This feature would add Exness to the list of supported brokers/servers within PF1's connectivity options, enabling users to link their Exness accounts for comprehensive trading analytics, performance tracking, and portfolio management alongside their other prop firm and personal accounts. The integration should support all standard PF1 functionality including trade importing, real-time data synchronization, performance metrics, and dashboard reporting to ensure Exness account holders can fully utilize the platform's trading analytics and management capabilities.