feat(docker): add dockerfile best practices

[0xlildoudou]

Hi,

I have add Dockerfile best practices (https://docs.docker.com/build/building/best-practices/)

Check with Hadolint:

$ docker run --rm -i hadolint/hadolint hadolint "$@" - < Watcher/Dockerfile 
-:25 DL3059 info: Multiple consecutive `RUN` instructions. Consider consolidation.
-:28 DL3059 info: Multiple consecutive `RUN` instructions. Consider consolidation.

https://github.com/hadolint/hadolint

[ygalnezri]

Hi @0xlildoudou,

Thank you for your contribution! We are happy to accept the proposed modifications to the Watcher/Dockerfile as they align well with the recommended practices. However, we would like to keep the current version of the docker-compose.yml file as it is, specifically with the following line that specifies the image:

image: felix83000/watcher:latest

We believe this configuration works best for our current setup. Once you update the pull request with the modifications to the Dockerfile while keeping the docker-compose.yml unchanged, we will be happy to accept it.

Kind regards,
Ygal