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GH-34186: [Go] Add arrow.MapOfWithMetadata to support (#34207)

@ zeroshade - issue #34186

The signature of MapType constructor is func MapOf(key, item DataType) *MapType. The field MapType.value is private and the pointer returned by MapType.ValueType doesn't give access to the fields of the underlying StructType.

I propose to add an additional constructor to specificy these metadata with the following signature:
```go
func MapOfWithMetadata(
  keyDT DataType, 
  keyMetadata Metadata, 
  valueDT DataType, 
  valueMetadata Metadata,
) *MapType
```
* Closes: #34186

Authored-by: querel <l.querel@f5.com>
Signed-off-by: Matt Topol <zotthewizard@gmail.com>