In order to make the intent of the component clearer, the JsonEncoder component should be renamed to JsonStreamer, as its main goal is to handle JSON streams as efficiently as possible.

In that way, it'll be harder for developers to get confused between this component and the Serializer's JSON encoder.

In that PR, the following public API has been updated:

• EncoderInterface::encode() has been renamed to StreamWriterInterface::write()
• DecoderInterface::decode() has been renamed to StreamReaderInterface::read()
• the JsonEncoder class has been renamed to JsonStreamWriter
• the JsonDecoder class has been renamed to JsonStreamReader
• the JsonEncodable attribute has been renamed to JsonStreamable
• the EncodedName attribute has been renamed to StreamedName
• ValueTransformerInterface::getJsonValueType() has been renamed to ValueTransformerInterface::getStreamValueType()
• ValueTransformer::$toJsonValue has been renamed to ValueTransformer::$nativeToStream
• ValueTransformer::$toNativeValue has been renamed to ValueTransformer::$streamToNative