[CI/CD] Build/Publish a synkronus-cli docker image for use in custom_app ci/cd pipelines

[r0ssing]

Component

• formulus (React Native mobile app)
• formulus-formplayer (React web app)
• synkronus (Go backend server)
• synkronus-cli (Command-line utility)
• Documentation
• Other (please specify) --> CI/CD

Feature Description

Build/Publish a synkronus-cli docker image for use in custom_app ci/cd pipelines.
If we publish a ready-to-use docker image of the cli, then we could simply pull that from the demo apps (and other custom_apps') pipeline

Problem Statement

Having a pre-built image would save time in custom_apps' ci/cd pipelines, since they would not have to pull the ode repo and build it themselves....