Restructure log handling

- Introduce new module (lux_logs) to cope with log file internals
- Split summary log into three parts: config, result and summary.
- Extend the tail command in the debugger to enable viewing of the new logs
- Generate html logs on the fly after each test case
Maintain link to latest_run even when using --log_dir
The new --extend_run can be used to extend logs of an old run

The new outcome of the new run will be appended to the old summary log