Enhanced CLI Plugins

[attiasas]

• All tests passed. If this feature is not already covered by the tests, I added new tests.
• All static analysis checks passed.
• This pull request is on the dev branch.
• I used gofmt for formatting the code before submitting the pull request.

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• Adding README.md to help using and implementing plugins.
• Adding Namespace to App allowing to create sub commands at the plugin.
• Adding PrintCommandHelp method to Context to allow for a dynamic way to print the command usage help for the plugins if an error occur while parsing the context for the command.

Enhancements have been made in generating automatic usage for help regarding CLI Plugins to encompass broader scenarios:

• Arguments can be specified as optional (for help usage in commands such as download).
• String flags can be designated as mandatory (for help usage in commands like offlineupdate).
• Arguments can now be substituted with flags based on their names, generating usages for both scenarios (for help usage in most commands using the specFile flag instead of arguments, such as scan, download, move, etc.).
• Commands can be concealed (Hidden) from printing in usage help (for deprecated commands like audit-go, xr scan, etc.).
• In cases not adhering to the specially generated usage, you can specify UsageOptions to manually add to or replace the generated usages (for help usage in commands such as ocstartbuild).
• Adding Category to commands.

[github-actions]

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🐸 JFrog Frogbot

[yahavi]

Looks very good!

• Please consider my inline comments.
• Let's also talk about the design tomorrow
• I think it is important to document in this or future PR instructions in the CONTRIBUTING.md how to contribute a command.