Use of assert!() and debug_assert!()

[Wrench56]

Previously, we decided during charlotte_core development that assert!() macros are to be avoided. They are unambigious, coming from a C environment might make you think that they are compile time asserts, in reality, they are runtime checks in Rust. Additionally, they panic, the whole point of this repository is to provide a non-panicing alloc module. Note: debug_alloc!() is NOT included in release builds, but they are included in debug build. I believe we should not be using any of the assert!()-s to keep things simple. Especially in this library, since panicing here is fatal for the OS.

Files such as lib.rs do use debug_assert!() statements, please either remove them, or even better, somehow check them but without panicing. Returning a Result is one way of fixing these things, another would be to use the already discussed "callback logger".