[Feature] option to ignore 404 errors

[TristanWasTaken]

Is your feature request related to a problem? Please describe.
I'm always frustrated when a single image like the credit page is missing and the whole chapter download fails. I will have to get the chapter manually anyways.

Describe the solution you'd like
An option in the settings to ignore 404 errors and save the chapter anyways.

Describe alternatives you've considered
An "ignore errors" option when you retry to download a failed chapter.

Context (please complete the following information):

• Version: 6.1.7

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

[Sheepux]

added to haruneko's features tracking