Mirror Maker 2 should use PEM files directly instead of using PKCS12 files

[scholzj]

As part of our move to use PEM files rather then PKCS12 files, we should migrate MM2 to use the PEM files instead of PKCS12 files. As MM2 is based on Connect, it already uses PEM files for the Connect part. But the MM2 connectors are still deployed with the use of PKCS12 files. This should be addressed.

[im-konge]

Marking this as triaged based on the rules of asynchronous issue triage.