The default implementation of EncryptedXml doesn't support using the RSA
key from X509Certificate to decrypt xml unless that cert is in the X509
CurrentUser\My or Localmachine\My store. This adds support for
decrypting with the X509Certificate directly. This is useful for Linux
(often Docker) scenarios, where the user already has a .pfx file, but
may not have added it to X509Store.
Nate McMaster