Using sg for start agent 

Change agent start command to use sg 

feature: Change version on dockerhub 

feature: Add hostname if INSTANCE_ID not set and update README.md 

feature: Add hostname if INTANCE_ID not provided and update README.md 

fix: Install folder path and update README.md 

 Optimize: Less versions push on dockerhub 

 feat: remove push on dockerhub when not a tag