[Suggestion] Official docker image on docker hub

I think it would be beneficial for the whole community to have an official `Aurelia` docker image in which some services like `aurelia-cli` are installed by default.

This will help them to be able to have multiple images with different CLI version, side by side, and it could help them to facilitate the CI/CD pipeline by focusing on their application's requirements for dockerization rather than thinking of which aurelia-cli or compatible versions of its dependencies to be installed.

A simple suggested docker image could be built using the following:

```Dockerfile
FROM node:12
ENV NODE_ENV development

RUN npm install -g yarn
RUN npm install -g webpack
RUN npm install -g aurelia-cli@1.0.1

WORKDIR /app

EXPOSE 8080

CMD [ "bash" ]
```
Then we could have different versions, with different configurations pre-installed so that developers are able to test their application with those configurations.

**/cc** @EisenbergEffect

Start by reviewing the proposed Dockerfile in the issue, including its Node 12 base image and globally installed yarn, webpack, and aurelia-cli. Define which CLI versions and configurations are required, then verify that the resulting image variants can be published and used for CI/CD.

Written by the indexing model from the issue text.