Allow saving just a certificate to a Java KeyStore.

[danielfischeroctopus]

Prerequisites

• [x] I have searched open and closed issues to make sure it isn't already requested
• [x] I have discussed this in #feature-discussion or #backlog and the consensus is that this is something we plan on adding in the near future
• [x] I have written a descriptive issue title
• [x] I have linked the original source of this feature request
• [x] I have tagged the issue appropriately (area/*, kind/enhancement)

The enhancement

Currently when adding certificates to Java KeyStore, we only allow for saving public/private key combinations. We should allow for just saving certificates.

Links

https://secure.helpscout.net/conversation/927490582/48579?folderId=845288

[mcasperson]

Saving key pairs is done in https://github.com/OctopusDeploy/Octopus.Dependencies.Java/blob/master/src/main/kotlin/com/octopus/calamari/utils/impl/KeystoreUtilsImpl.kt#L75.

The additional functionality would be added with a call to setCertificateEntry().

[Marcus-James-Adams]

From an end-user point of view, this is particularly useful when adding trusted public keys to trusted keystores.

[jtognazzi]

This would be usefull !