replace "data center" and "city" with "AZ" and "region" (#12872)

[ti-chi-bot]

This is an automated cherry-pick of #12872

What is changed, added or deleted? (Required)

• Replace "data center" and "city" with "AZ" and "region" in the following three docs:
  • multi-data-centers-in-one-city-deployment.md
  • three-data-centers-in-two-cities-deployment.md
  • two-data-centers-in-one-city-deployment.md
• Update medias: media/multi-data-centers-in-one-city-deployment-sample.png and media/three-data-centers-in-two-cities-deployment-03.png

Which TiDB version(s) do your changes apply to? (Required)

Tips for choosing the affected version(s):

By default, CHOOSE MASTER ONLY so your changes will be applied to the next TiDB major or minor releases. If your PR involves a product feature behavior change or a compatibility change, CHOOSE THE AFFECTED RELEASE BRANCH(ES) AND MASTER.

For details, see tips for choosing the affected versions.

• master (the latest development version)
• v7.0 (TiDB 7.0 versions)
• v6.6 (TiDB 6.6 versions)
• v6.5 (TiDB 6.5 versions)
• v6.4 (TiDB 6.4 versions)
• v6.1 (TiDB 6.1 versions)
• v5.4 (TiDB 5.4 versions)
• v5.3 (TiDB 5.3 versions)
• v5.2 (TiDB 5.2 versions)
• v5.1 (TiDB 5.1 versions)
• v5.0 (TiDB 5.0 versions)

What is the related PR or file link(s)?

• This PR is translated from: update deployment docs docs-cn#11762, multiple AZs in two regions: fix the topology example docs-cn#13384
• Other reference link(s):

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

[ti-chi-bot]

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[Oreoxmt]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 4027316