Backport http stream content size #120246

[mhl-b]

Backport #120246.

Netty's HttpObjectAggregator handles for Expect: 100-Continue and chunked oversized requests besides aggregating parts. But HTTP stream handling does not use aggregator and we plan to remove it completely. That means we need to handle these cases by ourself.

This PR introduces Netty4HttpContentSizeHandler that handles expect-continue and oversized requests in the same way as HttpObjectAggregator. Some parts are copied from netty's code and simplified for our usage. Follow up on #117787 split into smaller pieces.

Once we completely switch to HTTP stream this handler will replace HttpObjectAggregator. For now there is conditional logic between stream and aggregation.

There is an interesting interaction between HttpRequestDecoder and HttpObjectAggregator . When aggregator responds with 413-too-large to expect-100-continue it resets HttpRequestDecoder through userEvent in pipeline.
Aggregator sends event and Decoder resets state.
This reset is required to avoid treating subsequent request as content of rejected request. But this is private code. Public interface is HttpRequestDecoder#reset(), so Netty4HttpContentSizeHandler requires explicit access to decoder and reset.