Fixes for dreamforce

[mdonnalley]

What does this PR do?

• Generate unit test by default for new commands
• Remove copyright headers for 3PP

What issues does this PR fix or reference?

[skip-validate-pr]

[iowillhoit]

QA NOTES

• 🟢 new_command.test.ts file created by default
• 🟢 If external, new commands do not add the copyright to generated files
• 🟢 Copyright is removed from all files when generating a new external plugin
• 🟢 ./.eslintrc.js has the copyright rule removed on new external plugins
• 🟢 Internal plugin files are correct
• 🟡 Had minor troubles with the copyright still existing on new command files in my existing external plugin. Reason was because the .eslint rule was not removed at plugin creation. The copyright text was not there at generation, but the sf-lint --fix was adding it back. This is an edge case and probably can be ignored. We could consider removing the --fix on dev generate command