Resolve "Improve H002 (unused and redundant indexes). Also adjust H001 (invalid indexes)"

Description

Report H002 reworked. Test db dump improved.

Related issue

https://gitlab.com/postgres-ai-team/postgres-checkup/issues/322

Examples

https://gitlab.com/postgres-ai-team/postgres-checkup-tests/blob/master/322-dmius-h00x-improve/md_reports/1_2019_02_25T09_42_00_+0000/Full_report.md#postgres-checkup_H001 Slack: https://postgres-ai.slack.com/archives/CE6NYN64W/p1550514376021700?thread_ts=1550513474.020800&cid=CE6NYN64W

Closes #322 (closed)