Adds CLI argument to allow remaining downloads to continue after receiving a --timeout error

[xunker]

Adds a new command line arg (-C or --continue-after-timeout) that will let the download process continue after a timeout error is raised within parse_page().

My use case:

I have sub-pages under a published Notion page that I don't want to be visible to the whole world.
I can "unpublish" those specific pages so Loconotion will skip them (it will time-out when trying to load them) and continue parsing all the remaining sub-pages.

It looks like my text editor also removed some trailing whitespace, I opted to leave those changes in this commit.