Various TLS related updates (#16982)

[ti-chi-bot]

This is an automated cherry-pick of #16982

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 server: fix tls setup and error log tidb#15287 and *: move config file option require_secure_transport to sysvar tidb#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)

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• v5.0 (TiDB 5.0 versions)

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

• This PR is translated from: Various TLS related updates docs#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

[Oreoxmt]

/approve

[ti-chi-bot]

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