[jaeger-operator] Allow setting the Certificate Issuer Kind

[fernferret]

What this PR does

Allow setting the Certificate Issuer kind to ClusterIssuer while retaining the default type of Issuer.

If certs.issuer.create=true is set, the Certificate's Issuer Kind will always be Issuer, since this change does not allow the built-in issuer's kind to be modified.

Which issue this PR fixes

• fixes #386

Checklist

• [x] DCO signed
• [x] Commits are GPG signed
• [x] Chart Version bumped
• [x] Title of the PR starts with chart name ([jaeger] or [jaeger-operator])
• [x] README.md has been updated to match version/contain new values