Support FFI / C Data Interface for MapType

[wjones127]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

MapType was added in #491, but is not yet supported in C Data interface. Users will currently experience this error:

arrow-rs/arrow/src/datatypes/ffi.rs

Lines 266 to 269 in ca5fe7d

	other => Err(ArrowError::CDataInterface(format!(
	"The datatype \"{:?}\" is still not supported in Rust implementation",
	other
	))),

Use use this FFI to move schemas from Rust-land to PyArrow-land in delta-rs.

Describe the solution you'd like

Add map type to current handling.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
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