Apply some dockerfile best practices

[sbellem]

• use COPY instead of ADD
• run apt-get update before apt-get install to refresh the cache
• clear up the apt cache (/var/lib/apt/lists) to reduce the image size

Some Dockerfile best practices links

ADD or COPY

For other items, like files and directories, that don’t require the tar auto-extraction capability of ADD, you should always use COPY.

apt-get

Always combine RUN apt-get update with apt-get install in the same RUN statement.

In addition, when you clean up the apt cache by removing /var/lib/apt/lists it reduces the image size, since the apt cache isn’t stored in a layer. Since the RUN statement starts with apt-get update, the package cache is always refreshed prior to apt-get install.

Sort multi-line arguments

[dartdart26]

@david-zama Could you please have a look?

[dartdart26]

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