Feature request: include package name or package url in arrow metadata

[ericphanson]

Since Legolas schemas are defined in code, if you just have a table, Legols.read will tell you the schema isn't defined and you need to load the package, but it won't tell you which package (brought up by @a-cakir in the engineering roundtable). Namespacing can help, but it could be more clear if we actually just put the julia module name where the @row was defined, and/or the package name, and/or the repo url. We could put this in the Arrow metadata and use it to give a more precise error message.

[hannahilea]

this would be a game-changer!

[jrevels]

probably a good idea

also ref #1

[hannahilea]

#47 is esp important if/when this gets implemented (thanks @palday)

[jrevels]

xref #54 (comment)

[ericphanson]

just to bump this; I think we should have some metadata at least for julia users to know what package provides a schema, so undefschema errors can say "load package X".

(came up in an internal project)