CircleCI integration

Create CircleCI config file which clones SingularityNET repositories and builds them.
It can be initially based on the wiki page with Tutorial: Build and deploy SingularityNET locally
https://github.com/singnet/wiki/wiki/Tutorial:-Build-and-deploy-SingularityNET-locally

This CircleCI pipeline can be run on daily basis or be triggered by pull request from modules which it depends on.