Add a config flag to suppress log messages irrelevant to pre-upload usage

[eshellman]

examples:

INFO:root:There is no Project Gutenberg eBook number for this book in the source file.
INFO:root:There is no Project Gutenberg eBook number for this book in the source file.
INFO:root:No PG header found. This is an ERROR for white-washed files.
INFO:root:No PG footer found. This is an ERROR for white-washed files.
INFO:root:No boilerplate found in file:///htdocs/ebookmaker/cache/20250103001349/chasl-utf8.html
INFO:root:No pg-header found, not inserting a generated one.
INFO:root:No pg-footer found, not inserting a generated one

[rtonsing]

Just to add my whining, the only messages in this report that are useful as a PPer or WWer are the "WARNING:root:External link" ones. But I have to wade through all of them.
The ALTTEXT ones are weird, these images HAVE alt text.
Gleanings.zip.output.txt

[eshellman]

sorry about the ALTEXT entries, these are meant for feeding into mitigation platforms, and it turned out to be difficult to write a separate log. I will be able to omit them for online ebookmaker using the config flag. Thanks for reminding me.

…

On Jan 12, 2025, at 1:16 PM, Robert Tonsing ***@***.***> wrote: Just to add my whining, the only messages in this report that are useful as a PPer or WWer are the "WARNING:root:External link" ones. But I have to wade through all of them. The ALTTEXT ones are weird, these images HAVE alt text. Gleanings.zip.output.txt <https://github.com/user-attachments/files/18390523/Gleanings.zip.output.txt> — Reply to this email directly, view it on GitHub <#251 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAHCGMPQUKDBA6LJ3URV2432KKWQ7AVCNFSM6AAAAABURZZ2MGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKOBVHA2TOMBTG4>. You are receiving this because you authored the thread.