GRAMEX-198 ⁃ Build matrix for Docker images

[jaidevd]

trafficstars

We should explore the possibility of supporting the following variations of the Gramex Docker image

• [x] Ubuntu + Conda + Gramex + all apps (the default)
• [ ] Same as above with only UI component
• [ ] Alpine + conda + Gramex + all apps
• [ ] Same as above with only UI components

They all have their applicability.

In addition, it should be possible to run Gramex as a non-root user in all these images.