[server] Support configurable time partition format for auto-partitioned tables

[wattt3]

Purpose

Linked issue: close #3191

Brief change log

• Add 'table.auto-partition.time-format' to override the unit partition value format
• Validate pattern syntax at table creation
  • the zero-padded / lex-orderable contract is the users's responsibility. (retention compares partition names via TreeMap)

Tests

API and Format

Documentation

[wattt3]

@luoyuxia PTAL, thanks.