sql/query.md: new page

Summary

• sql/query.md: new page

Address changes from:

• picodata@6d851115 — picodata 24.3.0-120-g6d851115
• sbroad@3c9ff0a5

---

• Close #244
• Cherry-pick to: 24.5 / 24.4 / 24.3
• Staging:
  • .../reference/sql/query/
  • .../reference/sql/select/
  • .../reference/sql/select/#scan
  • .../reference/sql/select/#expression
  • .../reference/sql/dql/
  • .../reference/sql/insert/
  • .../reference/sql/update/
  • .../reference/ansi_sql/#additional_features
  • .../sql_index/