build: stops ignoring .env.development and .env.production files from docker context so env variables get set during react app build.
* this fixes the issue where Browse Libraries button link was broken in
docker/self-hosted versions of excalidraw
* .eslintrc.json is required to build using react-scripts
* Remove the extra "deps" step
This step can be done as part of the build (faster and more reliable).
* Add a GitHub Actions to build the Docker image
Make sure that "docker build" is working on every pull request before landing on master.
* Update package-lock.json
* Add .prettierrc in the Docker image to avoid warnings in the build step
* Revert "Update package-lock.json"
This reverts commit 7ef2eaadfae610771987bc8155670b895c139e7b.
* Make sure that the 'node_modules' layer can be cached
if package and package-lock.json didn't changed
