Feature/SK-1254 | add .fednignore for fedn package

[Wrede]

This pull request includes changes to multiple client examples and the fedn CLI to improve the handling of ignore patterns and package creation.

Client Example Updates:

• Added .ignore files to various client examples to exclude __pycache__, data directories, and specific venv directories. [1] [2] [3] [4] [5] [6] [7] [8]
• Updated python_env.yaml files to change the environment names to use a dot prefix, ensuring consistency across examples. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]

fedn CLI Enhancements:

• Introduced a new function create_tar_with_ignore in package_cmd.py to create tar archives while respecting ignore patterns specified in .ignore files. This function logs the files being added and handles potential errors gracefully.
• Modified the create_cmd function to use the new create_tar_with_ignore function, improving the robustness of the package creation process.

[benjaminastrand]

Looks very good! I would consider calling the .ignore file something more descriptive like .packageignoreor .fednignore?

[benjaminastrand]

Awesome job man! Great improvement to our software! :)

[Hovstadius]

Running fedn package create -p client creates the .tar and places it inside of the client folder, not the current working directory. Is this an intended update or an unintended bug?

[Wrede]

Running fedn package create -p client creates the .tar and places it inside of the client folder, not the current working directory. Is this an intended update or an unintended bug?

intended.

[FrankJonasmoelle]

Changes work for my example(s)