Index modifiers and maybe timestamp of modification

[majsan]

Add an internal fields where a compressed version of the entry history is added.

Either just a list of modifiers: modified_by: ["user1","user2","user3"]

Or preferably, a nested field with user and modification timestamp:
modified: [ {user: "user1", timestamp: 1728377906}, user: "user2", timestamp: 1728377907} ]

so that one can do queries like:

@modified(and(equals|user|user1||gte|timestamp|1728377000))