Add additional info regarding Manual Media Files Import procedure

[IAmABakuAMA]

Relevant section: Docs > settings > actions > Manual Media Files Import > Method 1 (https://docs.tubearchivist.com/settings/actions/#manual-media-files-import)

Per https://discord.com/channels/920056098122248193/1347902272063012885/1347929962656829440, the documentation for importing YouTube videos manually is slightly unclear for beginners, specifically the section regarding the <video-ID>.info.json sidecar. A couple of notable fields that could be added to improve clarity:

• upload_date expects a "YYYYMMDD" format, without any hyphens or separators. The date needs to be surrounded by double quotes.
• description requires double quotes around the value.
• categories is the "video category" value, which doesn't appear to be displayed on the web GUI/frontend any more. Requires double quotes.
• view_count expects a raw string, with no commas between decimal places, for instance 3333333 instead of 3,333,333 This value doesn't require quotes around the value.