Set Parquet key-value metadata

[kylebarron]

Should be able to set metadata with:

import {
  WriterProperties,
  WriterPropertiesBuilder,
} from "./pkg/esm/parquet_wasm.js";

let props = new Map<string, string>();
props.set("geo", "...");
let writerProps = new WriterPropertiesBuilder()
  .setKeyValueMetadata(props)
  .build();

[github-actions]

Asset Sizes

Asset	Uncompressed Size	Compressed Size
async_full/parquet_wasm_bg.wasm	5.45MB $\color{red}\textbf{+1.28KB +0\%}$	1.27MB $\color{green}\textbf{-5.83KB -0\%}$
slim/parquet_wasm_bg.wasm	3.46MB $\color{red}\textbf{+1.45KB +0\%}$	545KB $\color{red}\textbf{+977B +0\%}$
sync/parquet_wasm_bg.wasm	4.74MB $\color{red}\textbf{+1.41KB +0\%}$	1.03MB $\color{green}\textbf{-590B -0\%}$