Change loader log file location

[Jemale]

I think this should be reversed, such that the log file is always called ze_loader.log but you can override where it gets put. I can work on this soon.

I'm not sure I understand, if a user doesn't set ZEL_LOADER_LOG_FILE then the log file is #define LOADER_LOG_FILE_DEFAULT "ze_loader.log"

[lisanna-dettwyler]

What I mean is, eliminate ZEL_LOADER_LOG_FILE and introduce ZEL_LOADER_LOG_DIR. If it's not set, default to ~/.oneapi_logs. Rename LOADER_LOG_FILE_DEFAULT to LOADER_LOG_FILE. Reasoning is that I just think it's more likely that someone would want to change where the logs get put (like if running in a system where ~ isn't used/writable) than what our specific log file name is.

[Jemale]

The default location was now being changed to the user home, e.g. C:\Users\jlockett.oneapi_logs. That was failing due to the same issue in the linked bug