REST Asset Search JSON API

Acceptance

• This sub-resource accepts the same inputs as NEXUS-11745 (search REST endpoint), except it replies with an ordered JSON list of assets
• Until NEXUS-11744 (order by 'latest') is implemented, it's fine if the ordering is unspecified (e.g. it emerges from Elastic Search scoring)

Non-Requirements

(Just for clarity)

• We're trying to avoid format-specific logic
  • For maven, if people want the 'jar' (which was a default in NXRM2), then they specify that as a search parameter. maven.extension-jar
  • Primary maven artifacts, as designated in POMs, aren't considered. Users have to ask for what they want.
  • Similarly for PyPI, it's users' responsibility to know if they want an egg, a wheel, if they care, etc. and to specify the search accordingly