Adds LinqHelper, ReflectionHelper

What's Changed

• Adds LinqHelper, ReflectionHelper
• Create CODE_OF_CONDUCT.md by @hannesbarbez in #1

New Contributors

• @hannesbarbez made their first contribution in #1

Full Changelog: https://github.com/hannesbarbez/BarbezDotEu.Generic/commits/3.0.0