🔎 AS - For files: Check for existing DAV Search functionality (date search, people/owner)

[sorbaugh]

Copied from #39162

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For things like date range, we have to make sure it works across different apps like Files, Calendar, Contacts, Talk, Mail etc with different types of dates, so we need to define which date it is for the relevant type:

Files: modification date (probably more relevant than creation date)
Calendar: event date (probably more relevant than creation date)
Deck card: due date (probably more relevant than creation date, if it exists)
Talk: message date
Mail: message date
Contacts: ? birthday
General fallback would be "Modified date"
etc. …
For people:

Files: owners and sharees
Calendar: participants
Deck card: assignee
Talk: message poster and/or person replied to
Mail: sender and recipients
Contacts: the contact itself, possibly manager also
General fallback would be sharing