Separate the options `--ignore-errors` and `--no-abort-on-error`

Separate the options `--ignore-errors` and `--no-abort-on-error`

In youtube-dl, `-i` ignores both download and post-processing error, and
treats the download as successful even if the post-processor fails.

yt-dlp used to skip the entire video on either error and there was no
option to ignore the post-processing errors like youtube-dl does.

By splitting the option into two, now either just the download errors
(--no-abort-on-error, default on CLI) or all errors (--ignore-errors)
can be ignored as per the users' needs

Closes #893