Create utility to gather basic project metrics

[neeraj-laad]

It would be nice to have some utility scripts that can gather project metrics like:

DockerHub

• image downloads for each stack
• update timestamps for each stack

GitHub

• forks - appsody/appsody and appsody/stacks
• start - appsody/appsody and appsody/stacks
• watchers - appsody/appsody and appsody/stacks

GitHub Releases

• Download count for Appsody CLI binary (each platform)
• Download count for Appsody controller

Slack

• member count

Ideally, it would be good to have the data in a format that can be imported into a spreadsheet of some sort to allow further processing or visualisation (if needed).