Make http header list size configurable in HTTP client for HTTP2

[Pavlov7]

Description

This PR adds configurable maxHeaderListSize property to HTTP client configuration for HTTP2.

Added maxHeaderListSize configuration property with getter/setter methods.
Updated Http2FrameCodec instantiation to use the configurable header list size.

Considerations

Can be configured via micronaut.http.client.http2.max-header-list-size property.

[yawkat]

Please take a look at Http2Settings and implement it similar to that config.

[Pavlov7]

Please take a look at Http2Settings and implement it similar to that config.

The main difference I see between Http2ClientConfiguration and Http2Settings is that Http2Settings is holding an instance of io.netty.handler.codec.http2.Http2Settings and getters and setters are reading from/writing to that instance.
I am not sure whether it would be better for Http2ClientConfiguration to also start holding an instance of io.netty.handler.codec.http2.Http2Settings, because then the micronaut-http-client-core module has to start depending on micronaut-http-netty so that it transitively starts depending on io.netty.codec.http2

[Pavlov7]

Please take a look at Http2Settings and implement it similar to that config.

The main difference I see between Http2ClientConfiguration and Http2Settings is that Http2Settings is holding an instance of io.netty.handler.codec.http2.Http2Settings and getters and setters are reading from/writing to that instance. I am not sure whether it would be better for Http2ClientConfiguration to also start holding an instance of io.netty.handler.codec.http2.Http2Settings, because then the micronaut-http-client-core module has to start depending on micronaut-http-netty so that it transitively starts depending on io.netty.codec.http2

^ @yawkat

[graemerocher]

@yawkat please review the feedback

[yawkat]

Yea you're right. My idea doesn't work.

[jdeex]

@Pavlov7 I think this one broke the consul client. It doesn't get any HTT2Configuration and tries to override the defaults causing a nullpointer. I set the 3 configuration options for max-header-list-size but HTT2Configuration is always null. Also did a quick fix to avoid the nullpointer on #12389, but not sure if that's the way you would like to go... We cannot upgrade to latest versions because of this