feat(transparent-proxy): add option to uninstall transparent proxy

[bartsmykla]

Tip

I recommend reviewing each commit individually, as I've organized the work into self-contained, descriptive commits for easier understanding.

Closes #6093

Add logic for Transparent Proxy uninstallation/cleanup

1. Uninstallation/Cleanup Logic:
   • Added functionality to clean up and uninstall the transparent proxy setup
   • Removed iptables rules and chains related to the transparent proxy, ensuring only relevant rules and chains are removed based on the presence of iptables comments
   • Validated the new rules after cleanup and restored them if they are valid
   • Addressed a known bug on Ubuntu 20.04 related to iptables-nft-restore --test failing with more than two tables, adding appropriate handling for this issue
2. Installation Process Improvement:
   • Added a cleanup step at the beginning of the installation process to remove any existing transparent proxy rules before setting up new rules
3. Detailed Logging:
   • Improved log messages for better clarity and debugging
   • Logged the successful completion of the transparent proxy cleanup process

Improvements in logging

• Removed redundant log after restoring iptables: iptables set to divert the traffic to Envoy
• Consolidated log and error message content into single lines for easier searching in IDEs or code editors
• Updated Logger instances passed to initialization functions in configs to include appropriate prefixes ([iptables] or [ip6tables])

Add Tests for Transparent Proxy uninstallation

Remove unit tests for uninstalling Transparent Proxy

• Removed non-functional unit tests for uninstalling the transparent proxy that served only as placeholders due to difficulties in idempotently testing across environments

Remove unused string from cleanup signatures

• Updated function signatures as Cleanup no longer returns any output

Set IPv6 in DefaultConfig value to true

• Ensured the default installation of the transparent proxy supports both IPv4 and IPv6, aligning with the --ip-family-mode default value of dualstack

Refactor Executables initialization for better error handling and logging

1. Method Refactoring:
   • Split the writeRulesToFile method into createTempFile and writeToFile
   • Added createBackupFile for better modularity and reusability
2. Restore Functionality Enhancements:
   • Refactored restore, Restore, RestoreWithFlush, and RestoreTest methods for better iptables rule restoration and validation, incorporating improved error handling and logging
   • Implemented robust backup and restore mechanisms in RestoreWithFlush
3. Documentation Improvements:
   • Added detailed comments and descriptions for several functions to enhance code readability and maintainability

Enhance descriptions for Logger methods

• Improved comments and descriptions for the logger methods within the Logger struct for better readability and maintainability

Add new Logger methods Errorf and Infof

• Introduced Errorf and Infof methods to the Logger struct for formatted logging of error and information messages

Add RestoreTest method to InitializedExecutablesIPvX

• Added a method to run iptables-restore with the --test flag to validate iptables rules without applying them

Refactor iptables restore logic and add RestoreWithFlush method

• Refactored the logic for executing the iptables-restore command, introducing a new internal restore function to handle common restore logic, and added RestoreWithFlush method for scenarios requiring rule flushing

Remove the ability to change the iptables comments prefix

• Removed the configurability of the iptables comments prefix to simplify the uninstallation process and reduce the risk of errors

Checklist prior to review

• Link to relevant issue as well as docs and UI issues
  • Introduce logic to uninstall iptable rules #6093
• This will not break child repos: it doesn't hardcode values (.e.g "kumahq" as a image registry) and it will work on Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS
  • It won't
• Tests (Unit test, E2E tests, manual test on universal and k8s)
  • Don't forget ci/ labels to run additional/fewer tests
• Do you need to update UPGRADE.md?
  • There is no need
• Does it need to be backported according to the backporting policy? (this GH action will add "backport" label based on these file globs, if you want to prevent it from adding the "backport" label use no-backport-autolabel label)
  • There is no need