Add recommendations for option parsing

In C++ my experience says:

• If it is okay to use boost, use boost::program_options, it is a solid library.
• It is often not okay to use boost. The headers alone are > 50 MB 🙀 and contain > 13,000 files. And boost::program_options requires linking a precompiled library. This is massive weight and complexity for a build system just to parse options.
• So for lightweight C++ libs that might not otherwise have any dependencies we need to recommend a very lightweight option parsing solution.

/cc @GretaCB @joto @mapbox/core-tech @danpat

此 issue 未指定任何檔案、測試或進入點。研究輕量級的 C++ 選項解析方案，並根據已陳述的限制比較它們在相依性、標頭檔與連結方面的成本。完成的標準是記錄一份針對輕量級 C++ 程式庫的明確建議，同時說明何時仍適合使用 boost::program_options。