Update docker files to follow solar lint rules

[docbyte86]

"WORKDIR" instruction should be used instead of "cd" commands (docker:S6597)
In Dockerfile, instructions RUN, CMD, and ENTRYPOINT can contain long shell scripts chaining multiple commands, including the cd command for changing directories. Using WORKDIR instruction instead reduces the complexity of the above instructions and makes them easier to read, understand, troubleshoot, and maintain.

Cache should be cleaned after package installation (docker:S6587)
Docker images should only contain necessary data. The package index is optional for the correct working of the installed software. Storing an index also increases the size of the Docker image. It should be reduced to speed up deployments and reduce storage and bandwidth.

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ docbyte86
❌ Tobias Ramm

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[docbyte86]

@cognifloyd , kindly request an approval for this change or leave a comment. thank you very much