en,zh: remove docs about tidb-binlog and tikv-importer

[csuzhangxc]

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• [ ] v1.6 (TiDB Operator 1.6 versions)
• [ ] v1.5 (TiDB Operator 1.5 versions)
• [ ] v1.4 (TiDB Operator 1.4 versions)
• [ ] v1.3 (TiDB Operator 1.3 versions)

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