GPA: Add support to query a key from a command line argument.
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Description

KMail (and gpgol in the upcoming no-mime branch) call
kleopatra --query <fingerprint>
to show the details of a key.

This command either shows the details of a key if the key is available locally
or starts a keyserver search if it is not available.

As there is no such command in GPA i'm currently showing the message box:

"Could not find Kleopatra. Please reinstall Gpg4win with the Kleopatra component
enabled."

When someone clicks on key details in GpgOL and Kleopatra is not found.

This is still true even after the latest changes to GpgOL not to require Kleopatra or GPA through the UIServer protocol. The details dialog / search still uses Kleopatra or GPA as a fallback.