Push-to-Talk (PTT) Market Size, Share & Industry Analysis, By Component (Devices, Software, and Services), By Network Type (Push-to-talk over Cellular, and Land Mobile Radio), By Enterprise Size (SMEs, and Large Enterprises), By Sector (Public Safety & Security, Government & Defense, Transportation & Logistics, Energy & Utility, Travel & Hospitality, and Others (Manufacturing, Construction)) and Regional Forecast, 2020-2032