Update issue templates

Update README.md

#2 Example project is now included in repository

#3 On build the gdap file is now copied to output along with unity-adds.aar file from libs folder so you can just copy and paste the output

#4 Fixed issue when state was not reported to GDScript correctly also placement id was added to adsFinish signal

#1 - Updated plugin to be compatible with released godot version

Added download link to readme

Initial commit