Remove mandatory x509v3 Subject/Authority Key Identifiers in certificate(s) (#3181)

[ghost]

Remove mandatory check for x509v3 Subject/Authority Key Identifiers in imported certificate(s)

What does this PR do?

Fixes #3181

Which TC components are affected by this PR?

• Documentation
• Grove
• Traffic Analytics
• Traffic Monitor
• Traffic Ops
• Traffic Ops ORT
• Traffic Portal
• Traffic Router
• Traffic Stats
• Traffic Vault
• Other _________

What is the best way to verify this PR?

1. Start up a Traffic Ops environment with at least one HTTP_and_HTTPS delivery service.
2. Import a self-signed CA and a certificate that is signed by this CA. Make sure that the certificate does NOT contain the X509v3 Subject/Authority Identifer Key(s) extensions.
3. After importing the certs, view the certificate either via the API or in the DS sslkeys page of the Traffic Portal. The certificate field should contain a valid certificate.

Check all that apply

• This PR includes tests
• This PR includes documentation updates
• This PR includes an update to CHANGELOG.md
• This PR includes all required license headers
• This PR includes a database migration (ensure that migration sequence is correct)
• This PR fixes a serious security flaw. Read more: www.apache.org/security

[asfgit]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/trafficcontrol-PR/3043/
Test PASSed.

[asfgit]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/trafficcontrol-PR/3044/
Test PASSed.

[jhg03a]

This PR works for me

[ghost]

I've reviewed the existing unit test for this endpoint and it doesn't need to change IMO. I've also tested the following X509 certificate import scenarios on a test instance and all have been successful:

• X509v1 Single Self-Signed Certificate: CN only
• X509v1 Root CA Self Signed + Server Certificate Signed by Root CA
• X509v1 Root CA + Intermediate CA + Server Certificate Signed by Intermediate CA
• X509v3 Root CA Self Signed + Server Certificate (Test Both with and w-out SKI/AKI extensions)
• X509v3 Root CA Self Signed + Two intermediate CAs + Server Certificate (Test Both with and w-out SKI/AKI extensions)
• Imporrted various real certificates from a real prod system. All verify okay.

IMO this PR is ready to be merged.