Update dependencies; Fix #425

[Geogouz]

This commit basically cleans up a bit the project's Docker container definitions.

• It removes several packages that are no longer needed, such as , gcc, libnsl, and libaio (similar to dependencies: Remove unused libnsl and libaio from dev test image; Fix #7861 rucio#7867), which were likely required by cx_oracle only.
• It standardizes the Python package installations to use the python3 versions, for example, by replacing python-pip with python3-pip.
• Additionally, a minor typo in a file copy command was corrected, and license headers were added to some files.

Although I tested locally that the images are built successfully, it is important to test them while being used because in practice things might break during runtime too.

Couple extra points:

• It would be nice if we had a way to track which package requires what dependencies.
• It would be nice to have some CI/testing workflow where the pushed changes are evaluated in practice.