[C++] Migrate `arrow/ipc/metadata_internal.h` to `Result<T>`

[pitrou]

Describe the enhancement requested

Many APIs in arrow/ipc/metadata_internal.h take a T* out parameter for output and return a Status.

We should switch those APIs to return a Result<T> instead. Since those APIs are internal, we don't need to keep the old versions for compatibility.

Component(s)

C++

[Shally-Katariya]

Hi @pitrou, I'd like to work on this issue

[pitrou]

@Shally-Katariya Ok, I've assigned you. Feel free to ping me when you have a PR submitted.