Add Option to Customize PDF Display Settings During Import

[AltoRetrato]

Notes with many PDF files can become very unresponsive. In Evernote, you can choose whether a PDF file is shown as "Title" (aka "attachment"), which is equivalent to showing only the PDF title as a link in Obsidian; "Single page" (aka "pdf-pageByPage"); or "All pages" (aka "pdf-full"), with the last two being equivalent to showing a preview of the file. Currently, this information is not utilized during importing, so imported notes with PDFs have all them with preview enabled. This might break formatting (especially in tables) and cause performance issues on notes with many PDFs, requiring a lot of manual editing by users to fix. I'd suggest:

1. Ask the user if they want all PDFs (and possibly other types of documents) to appear as a links (e.g., [[path/to/test.pdf|test.pdf]]), as a preview (![[path/to/test.pdf|test.pdf]]), or, in the case of Evernote, as set in the .enex file.

For reference, the PDF display setting appears in .enex files like this:

<en-media style="--en-viewAs:attachment;" hash="..." type="application/pdf" />
<en-media style="--en-viewAs:pdf-pageByPage;" hash="..." type="application/pdf" />
<en-media style="--en-viewAs:pdf-full;" hash="..." type="application/pdf" />