Currently, if the runner failed to run the job, it just updates the status of the job to Failed without providing additional information.

We need to add status_code and status_description fields per job to store this information and display it properly in the CLI, etc.

1. status_code: Let's use it to store our own code that would indicate the reason for the status (similar to process exit codes). I suggest that we make this an integer field, where 0-255 values will be used in case the job is finished but returned a non-0 exit code, and 256-512 values we used for our own codes (Git authentication problem, backend authentication problem, unknown exception, no capacity, etc.

2. status_description: Let's use it to provide additional information for the status code (e.g. if the status code refers to an exception, provide it in this field).