Email Marketing Software Market Size, Share and COVID-19 Impact Analysis, By Channel (Business-to-Business (B2B) and Business-to-Customers (B2C)), By Deployment (On-Premise and Cloud), By Enterprise Size (Large Enterprises, and Small & Medium Enterprises), By Application (Email Lead Generation, Sales Reporting, Customer Management, and Others), By Industry (BFSI, IT and Telecommunications, Healthcare, and Others) and Regional Forecast, 2021-2028