Implement Table.Reader for Adbc

[josevalim]

This would allow it to be used conveniently in Livebook for querying without Explorer.

[josevalim]

@cocoa-xu I think we could improve our APIs a bit.

• I would expect Result.to_list to return a list but that doesn't make sense, so I believe the function should be removed?
• I would expect Column.to_list to return a list and do the whole view handling that is currently done inside Result.list_to_map

However, if we change the behaviour of Column.to_list, is there a use case for its current implementation, where it handles some lists but not all (i.e. not views)?

[cocoa-xu]

@cocoa-xu I think we could improve our APIs a bit.

• I would expect Result.to_list to return a list but that doesn't make sense, so I believe the function should be removed?
• I would expect Column.to_list to return a list and do the whole view handling that is currently done inside Result.list_to_map

However, if we change the behaviour of Column.to_list, is there a use case for its current implementation, where it handles some lists but not all (i.e. not views)?

Yea I think we can make this happen, let me check the failed test cases on CI

[cocoa-xu]

However, if we change the behaviour of Column.to_list, is there a use case for its current implementation, where it handles some lists but not all (i.e. not views)?

Okay I think it's fine to make this change, and it's also probably okay to just move Adbc.Result.list_to_map/1 to Adbc.Column.to_list/1

Essentially, we can just eliminate Adbc.Result.list_to_map/1 entirely, and then implement Adbc.Column.to_list/1 for the remaining types (like :list, :struct and probably all the primitive data types)