Configure the temporary directory instead of using \sys_get_temp_dir()

[dardael]

We have an error when using crunz with different projects on a same computer. The cache directory is computed in src/Application::getBaseCacheDir() using the function \sys_get_temp_dir(). So for all our projects, the cache is the same, but we need to have a different cache directory. (In our case we have some error)

A possible solution is to create an option in the configuration file and use it in the function src/Application::getBaseCacheDir().