quic: Add mechanism similar to waitUntilAvailable to create(Bi|Uni)directionalStream

The webtransport W3 spec allows to pass the option waitUntilAvailable to functions creating streams,
see e,g, here for a bidi stream:

https://www.w3.org/TR/webtransport/#dom-webtransport-createbidirectionalstream

The idea is that if the stream number flow control is exhausted, you have the option for waitUntilAvailable, which if it is set to false throw and tells the caller, that the flow control window for streams is exhausted.

(Alternatively, we can also supply a property to query the current budget).

The same is true for unidirectional stream.

@jasnell @pimterry
What would you think is a good api for this?
P.S: After the stream and session data flow control handling got attention. I will probably after this is decided, activate my stream number flow control tests on webtransport. As the stream number flow control is a another playing field that can easily lead to stalls. (Though I do not know if something is wrong.....)

Issue にリンクされている WebTransport 仕様と、既存の createBidirectionalStream および createUnidirectionalStream エントリポイントから始めてください。提案されている waitUntilAvailable の動作を、現在のストリーム番号のフロー制御処理および予算クエリという代替案と比較してください。両方向のストリームに対する合意済みの API があり、フロー制御ウィンドウが枯渇している場合と利用可能な場合を網羅するテストがあれば完了です。