Select multiple areas per page in `*_areas()`

[lindeloev]

extract_tables() can extract multiple tables per page. But extract_areas() and select_areas() allow for only one selection per page. It would be really convenient if you could select multiple areas, e.g., by holding SHIFT or CTRL. For now, I can get around it by doing multiple extractions of one table per page - no problem.

I have some PDFs like this where it currently includes the long text-line, messing up the format. So I want to just select the actual table:

Thank you for an almost magical package!