chore(IDX): test removing dependencies from the container

[cgundy]

I'm starting to do some refactoring work on the containers. Starting off, I'm slowly removing dependencies that we don't need. This removes:

• kubectl (the only reference I could find was here: https://github.com/dfinity/ic/blob/master/rs/rosetta-api/local/cluster/deploy.sh#L148 which installs kubectl if it is missing)
• python - since we don't seem to need it for CI anymore
• xtail - a dependency I added 1 year ago and know isn't required anymore