This commit introduces JSON streaming support which
consists of serializing HTTP request with
application/stream+json media type as line delimited JSON.
It also optimize Flux serialization for application/json by
using flux.collectList() and a single Jackson invocation
instead of one call per element previous strategy.
This change result in a x4 throughput improvement
for collection with a lot of small elements.
Issues: SPR-15095, SPR-15104
The base URI is ignored for requests that include a host.
WebClient exposes UriBuilder (rather than UriBuilderFactory) for
per-request URI building based on the base URI. That provides
full control to add or replace components of the base URI.
Leave only one static, no-arg build() method for access to a Builder.
URI-related preferences are now exposed on the builder itself.
Improve Javadoc with base URI examples.