Imported primary keys also have unknown trust level, when they have
been generated in other keyrings.
Later, we should decide whether to exclude any primary key with ultimate
trust level from any further change.
It may be of interest to copy WTreeTableNode items text content. These
cannot be selected with the mouse for copy to clipboard. The text is
here shown read-only in an extended auto-replaced WLineEdit.
In-place editing with a popup if user is allowed in app config file.
User must of course manage at least a private key. User identities of
target key may be selectively chosen. Optionally, certification may be
exportable and non-revocable.
