release-22.1: roachtest: declare encryption support as part of TestSpec

[renatolabs]

Backport 1/1 commits from #81483.

/cc @cockroachdb/release

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This commit introduces the EncryptionSupport field to TestSpec. By
setting this field, tests can declare whether they support being run
in a cluster with encryption enabled. Three options are available:

• EncryptionAllowed: test can run with or without encryption.
• EncryptionRequired: test can only run if encryption is enabled.
• EncryptionDisabled: test can only run if encryption is disabled (default).

This replaces the EncryptAtRandom field added earlier, which only
allowed tests to opt-in to random encryption.

In addition to this change, the values accepted by the --encrypt
flag in roachtest also changes. The only two valid values are:

• --encrypt=auto (default). Tests that support encryption
  (EncryptionAllowed) will run with encryption enabled.
• --encrypt=random (CI). Tests that support encryption
  (EncryptionAllowed) will run on a cluster which may or may
  not have encryption enabled.

The EncryptionSupport field should be the only way tests indicate
their relationship with encryption. The DontEncrypt field was
removed (it was not being used anymore at the time of this commit),
and all tests that set EncryptedStores directly were updated to use
EncryptionSupport accordingly.

Resolves: #79265.

Release note: None

---

Release justification: fix roachtest.

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Patches should only be created for serious issues or test-only changes.
• Patches should not break backwards-compatibility.
• Patches should change as little code as possible.
• Patches should not change on-disk formats or node communication protocols.
• Patches should not add new functionality.
• Patches must not add, edit, or otherwise modify cluster versions; or add version gates.

If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
• The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
• New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters.
• The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.

Add a brief release justification to the body of your PR to justify this backport.

Some other things to consider:

• What did we do to ensure that a user that doesn’t know & care about this backport, has no idea that it happened?
• Will this work in a cluster of mixed patch versions? Did we test that?
• If a user upgrades a patch version, uses this feature, and then downgrades, what happens?

[cockroach-teamcity]

This change is