Move asserts definition to crypto3

[makxenov]

Asserts from assigner could be used in another repositories as well, so we decided to move it to crypto3. Required steps:

• Copy the file into crypto3 Add asserts and other helpers for release builds. crypto3-block#77
• Remove the original file and update paths in assigner
• Update paths in zkllvm main repository

[aleasims]

It would be nice also to have this variant of todo function as well:

void todo(const std::string &msg, const char *filename, unsigned line);

Right now you can't write:

std::string s("world");
TODO("hello " + s);

I missed this variant when I was implementing this.

[aleasims]

We have some custom asserts defined in zkllvm-blueprint as well (here). Maybe we can replace them also. Blueprint is already using crypto3 library anyways.