Use more informative assert messages

[m-kus]

Added more context to some assert messages to simplify troubleshooting (to help identify the exact problem/location).

[fmkra]

That's a good point. I want to also modify other asserts e.g. public memory verification and maybe add a note in readme of common issues, e.g. selecting wrong layout leads to Invalid OODS etc.
I'll add some commits for that and we can merge it. Although, I wouldn't necessarily deploy with those changes until next release that has new features.