Digital Signage Market Size, Share & Industry Analysis, By Component (Hardware, Software, Content, and Services), By Deployment (On-Premise, Cloud), By Location (Indoor, Outdoor), By Product Type (Video Walls, Digital Posters, Kiosks, Billboards, and Others), By Industry Vertical (Retail, Corporate, Hospitality, Transportation, Education, Healthcare, Sports and Entertainment, and Others) and Regional Forecast, 2019-2026