Document tested and supported keystore types

[faandg]

Would be nice if this page listed the different types of supported keystores such as JKS, p12, ... Had to dive into a PR to confirm if p12 has been tested and is supported (link below).

Links

https://www.jenkins.io/doc/book/installing/initial-settings/#https-with-an-existing-certificate

• Link 1

[faandg]

Additional note; next to providing a list of compatible keystore formats, the example using JKS should probably be updated to use industry standard PKCS12 instead.

[meenaljain0303]

I can work on it @faandg