Drop support for `const char *` / `constStr`

[Compro-Prasad]

const char * / char * make the program vulnerable to many issues as we need to perform many checks and assign variables to have specific information about each string. So, a switch to std::string seems a viable option. If we really need to modify a string we can use c_str() to get a C like string and perform changes to it then assign the string accordingly.