Add InputStreamNormalizer
This patch adds InputStreamNormalizer interface to act as a unified API
displacing direct use of XmlParserStream/JsonParserStream.
It is modelled after the needs of RFC8040, yet it is useful in general,
as it supports essentially all use cases serviced by the *ParserStreams.
This core implementation logic is in
data.util.AbstractInputStreamNormalizer, which is a subclass of
AbstractCodecFactory.
The JSON-specific part is introduced as well, with the correspondign
NormalizedNodeParserTest.
JIRA: YANGTOOLS-1415
Change-Id: Id95b609257e1a8ab57e3d61896315e3211223176
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>