testing/manticoresearch: upgrade to 5.0.0

My comments about the changelog for the alpine package:

• We're not building the Manticore Columnar Library, so that update is not relevant here.
• They have a "new deb/rpm packages structure":
  • Our manticoresearch package is like their manticore-server-core (but with config from manticore-common): Just searchd and /etc/manticoresearch/manticore.conf.
  • We have a new subpackage: manticoresearch-stopwords, which is like their manticore-common package, but just the stopwords. This could theoretically be useful as a dependency for some other project which needs stopwords.

(I haven't yet found a daily use for manticoresearch, so I'm keeping it in testing, maybe someone else who's interested in manticoresearch/sphinx could adopt maintainership?)