Traffic Vault: Fix reencrypt utility to uniquely reencrypt ssl keys

[tcfdev]

Closes: #7158

A Traffic Vault utility called reencrypt allows for the ability to take previously encrypted values in the Traffic Vault DB and apply a new AES key for encryption. However, there was a bug that resulted in the "last" ssl key (misnomer) pulled from the DB during encryption would overwrite and wipe all other versions of ssl keys. This PR addresses said bug.

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Which Traffic Control components are affected by this PR?

• Traffic Vault (techinically a support utility call reencrypt)

What is the best way to verify this PR?

Previously existing "tests" should continue to work.

Manually verify:

1. Obtain a dump of an existing DB with the AES key that was initially used to encrypt the data (Or create a DB with sufficient data and use an AES key to encrypt said data).
2. Create a new, different AES key from the original.
3. Restore the DB into a test/verification DB location.
4. Run the reencrypt utility with the necessary connection info specified in the reencrypt.conf file, along with passing in the file path locations for the previous AES key as well as the new AES key.
5. Observe that the data column in the sslkey table has been reencrypted AND unique values exist for each version under a particular Delivery Service.

If this is a bugfix, which Traffic Control versions contained the bug?

PR submission checklist

• This PR has tests
• This PR has documentation
• This PR has a CHANGELOG.md entry
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[ocket8888]

Appears to fix the bug