Good practices to discuss in the course

[hageboeck]

A compilation of suggestions from #78

• Interfaces -I.3 (singletons) as well as I.11 & I.13 (avoid raw_ptr ownership transfer, avoid passing arrays without length)
• Errors - E.6 use RAII
• Classes - C.131 Avoid trivial getters/setters
• If you have a debate about how to do something, check core guidelines
• When to use free functions (anonymous namespace) and when member functions
• Keep headers clean, low number of includes? (Implement comments from #428 #508)
• Discuss SOLID principle at the end of OOP

[stale]

This issue or pull request has been automatically marked as stale because it has not had recent activity. Please manually close it, if it is no longer relevant, or ask for help or support to help getting it unstuck. Let me bring this to the attention of @klieret @wdconinc @michmx for now.