E-Commerce Software Market Size, Share, and Industry Analysis By Offering (Solutions (Payment & Billing Solutions, E-Commerce Management Platform, and End-to-End Platform) and Services), By Deployment Mode (Cloud-based and On-Premises), By E-Commerce Model (Business-to-Business (B2B) and Business-to-Consumer (B2C)), By Industry (Retail, Consumer Electronics, Fashion & Apparel, Food & Beverages, Healthcare, and Others), and Regional Forecast, 2026-2034