log densensitation

[xhebox]

Main tasks

Mark sensitive data with ‹..› when tidb_redact_log=marker, ‹ will be escaped to ‹‹, similar to ›. This is a new feature:

1. TiDB will produce logs with sensitive data marked with <>
2. Cloud or OP users could desensitive logs on their own by tidb-server sub commands or whatever.

It is basically because that users want the original log, and we (primarily tech supports) should only see desensitived logs.

• change tidb_redact_log variable to enum type #51307
• adapt parser.Normalize etc. https://github.com/pingcap/tidb/blob/master/pkg/parser/digester.go#L86 #51588
• adapt errors library https://github.com/pingcap/errors/blob/master/normalize.go#L25 #51310
• adapt other misc usages of tidb_redact_log. #51557
• adapt logutils #51641
• remove the old redact variable #51717
• change docs add explaination for log densitive feat docs-cn#16769
• a sub command for handling marker logs #51758

tests

• test https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/5435/pipeline https://tiprow.hawkingrei.com/view/gs/pingcapprow/pr-logs/pull/pingcap_tidb/51642/fast_test_tiprow/1767072980048809984
• *: additional marker tests for error redaction #52157
• admintest: additional redaction test #52158
• *: additional test for redact log and a fix  #52359 fix enlarged error redaction #52364

[JaySon-Huang]

@xhebox should we also update these related docs?

• https://github.com/pingcap/docs-cn/blob/1d6358a45add3e7339ad71feeb3cb0cad4a04bbf/log-redaction.md?plain=1#L10-L36
• https://github.com/pingcap/docs/blob/cd719695c040a41c1463f3fdba42f80aed8803d3/log-redaction.md?plain=1#L10-L38

[xhebox]

@xhebox should we also update these related docs?

* [pingcap/docs-cn@`1d6358a`/log-redaction.md?plain=1#L10-L36](https://github.com/pingcap/docs-cn/blob/1d6358a45add3e7339ad71feeb3cb0cad4a04bbf/log-redaction.md?plain=1#L10-L36)

* [pingcap/docs@`cd71969`/log-redaction.md?plain=1#L10-L38](https://github.com/pingcap/docs/blob/cd719695c040a41c1463f3fdba42f80aed8803d3/log-redaction.md?plain=1#L10-L38)

Oh, I don't there is a dedicated page for this.