Release v1.4.1

[csuzhangxc]

This is an issue tracking the tidb-operator v1.4.1 release.

Previous:

• Release v1.4.0 #4813

Pending PRs:

TODO:

• Update default version of TiDB Operator bump operator to v1.4.1 #4839
• Update TiDB version and tools (may include DM) version if necessary
  • no need
• Update the TiDB version and tools version in docs-tidb-operator repo
  • no need
• Update release notes en,zh: add v1.4.1 release notes docs-tidb-operator#2177
• Update Github Releases
• Build and publish docker images/helm charts
• Announcement (slack, email, etc.)
• Update TiDB Operator version in docs-tidb-operator repo (both for dev and stable branch)
  • bump operator to v1.4.1 for master docs-tidb-operator#2178
  • bump operator to v1.4.1 for release-1.4 docs-tidb-operator#2179