Improve artifacts processing

[NikolayS]

1. • nancy run should produce&save more artifacts:
   • pg_stat_statements numbers
   • pg_stat_kcache numbers
   • all standard pg_stat_*** numbers
   • postgresql.conf being used during the run

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2. • All artifacts should be in one single subdirectory to simplify its management. Artifact names should be simple & static, all "dynamic wording" goes to the subdirectory itself.
3. • Let's also add pgbadger.html (to simplify detailed analysis by human) – this is maybe temporary
4. • rename artifacts (static names), see More code divided on functions #96 (comment)

[NikolayS]

see also #96 (comment)

[NikolayS]

Таблицы pg_stat_** экспортировать в csv (см. http://www.postgresqltutorial.com/export-postgresql-table-to-csv-file/)