Various TLS related updates

[Oreoxmt]

What is changed, added or deleted? (Required)

1. The documentation of statements that have syntax like REQUIRE X509 didn't seem to be complete.
2. TLS is not only encrypting the connection, but is also providing other security properties like authentication. I've replaced some mentions of "encryption" with either "secure" or "TLS".
3. The startup messages no longer match the documentation. (related to https://github.com/pingcap/tidb/pull/15287 and https://github.com/pingcap/tidb/pull/34261)
4. The GRANT statement should not be used to create users and/or to modify users.
5. Some places weren't consistently putting things like REQUIRE in uppercase.
6. Add a note to tls-version about TLSv1.0 and TLSv1.1 deprecation.

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.

• [x] master (the latest development version)
• [x] v7.6 (TiDB 7.6 versions)
• [x] v7.5 (TiDB 7.5 versions)
• [ ] v7.4 (TiDB 7.4 versions)
• [ ] v7.3 (TiDB 7.3 versions)
• [ ] v7.1 (TiDB 7.1 versions)
• [ ] v6.5 (TiDB 6.5 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: https://github.com/pingcap/docs/pull/16267
• 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[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[Oreoxmt]

/cc @CbcWestwolf @hfxsd

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2024-04-07 06:49:54.457962386 +0000 UTC m=+772255.985502931: :ballot_box_with_check: agreed by hfxsd.

[Oreoxmt]

/approve

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Oreoxmt

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.0: #18022.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #18023.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.2: #18024.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #18025.