Only rename debug.log with errors relating to WPR

[jeawhanlee]

Is your feature request related to a problem? Please describe.
Right now we rename debug.log for every scenario that creates it whether the errors in the log are WPR related or not.

Describe the solution you'd like
We should check for errors in the debug.log that relates to WPR and rename it if any is found.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[MathieuLamiot]

Discussed as part of #54:

Expected behavior

• Rocket-E2E error log check must discard log files that contain only errors not related to WP Rocket: to identify them, we shoud look for wpr_, Rocket, rocket in the error text.
• Additionally, the error log check must have an option to discard a selected list of errors. For instance, in some test cases (install/uninstall/update/rollback) we want to discard errors like WordPress database error Table 'wp_wpr_rucss_used_css' already exists, No such file or directory, Failed opening, Cron reschedule event error for hook. This list must be maintainable by QA team.

If the error log check discards a log file (meaning there are only errors not related to WP Rocket and errors discarded if the option is enabled), then the error log file must not be kept and this check must succeed (not make the test fail).

[Mai-Saad]

AS per discussion with @jeawhanlee the part to ignore certain error will be handled at the helper plugin and it needs other GH