Per-minion schemas cause table count to explode (N minions * M metrics)
and the per-minion revocation story isn't worth it when retention is
short. Move all minions to a shared 'telegraf' schema while keeping
per-minion login credentials for audit.
- New so_telegraf NOLOGIN group role owns the telegraf schema; each
per-minion role is a member and inherits insert/select via role
inheritance
- Telegraf connection string uses options='-c role=so_telegraf' so
tables auto-created on first write belong to the group role
- so-telegraf-trim walks the flat telegraf.* table set instead of
per-minion schemas
- so-stats-show filters by host tag; CLI arg is now the hostname as
tagged by Telegraf rather than a sanitized schema suffix
- Also renames so-show-stats -> so-stats-show
Mike Reeves