[cdc] Support per-table configuration for MySQL database CDC

[lilei1128]

Purpose

• Add --table_conf_by_table for mysql_sync_database.
• Allow source tables to override global --table_conf table properties.
• Support per-table configuration in divided and combined modes.
• Reject per-table sink/job runtime options such as sink.parallelism.
• Document the new configuration and inheritance rules.

Tests

• Add parser unit tests for per-table configuration and duplicate keys.
• Add validation test for rejecting per-table sink configuration.
• Add MySQL CDC integration tests for divided and combined modes.
• Add coverage for per-table overrides and global configuration inheritance.

[JingsongLi]

Useful feature — per-table engine options remove the all-or-nothing --table-conf for database sync.

One issue: CdcActionCommonUtilsTest.testRejectSinkConfiguration() is missing its @Test annotation, so it never runs. It covers exactly the new validation (rejecting per-table sink.* keys), so it should be executed.

One behavior question: per-table keys that match no synchronized source table are silently accepted (parseTableConfigByTable just builds the map, and the override is looked up by exact table name). A typo such as oder:bucket=8, or a case mismatch, configures nothing with no signal at all. A warning listing unmatched keys (or validating against the discovered source tables) would save users a lot of debugging.