Feature/continuous delivery

[nionata]

• Created a owner Heroku account
  • Created a STEM-C pipeline with review apps, staging, and production
  • Created and added stem-c, stemc-staging, and stem-c-compile apps to the pipeline
  • Added Heroku PostgreSQL to the staging and production apps
• Setup automatic deployments
  • develop=> Staging
  • master=> Production
• Deployed the compile container to its app
• Configured heroku.yml and Dockerfile to bundle, build, and deploy the client and cms as a web container
• Updated the deployment documentation
• Removed the client Dockerfile and image from docker compose
• Updated strapi to the latest beta version 20.3
• Migrated all databases over to PostgreSQL
• Removed sqlite3 dependency to resolve CMS sqlite3 dependency  #14
• Updated client/config for all environment hosts
  • Created host helper to get the correct host based on the environment stage

Closes #12