Move OpenPGPCertificateCreationDialog to Libkleo

Allow to reuse it in gpgpass, kmail and gpgol.js

This also move some support classes:

• ErrorLabel -> exposed publicly, removed from Kleopatra
• Expiration -> exposed publicly, removed from Kleopatra
• KeyParameter -> exposed publicy, removed from Kleopatra
• Validator -> exposed publicy, removed from Kleopatra
• MultiValidator -> private, removed from Kleopatra
• AnimatedExpander -> private, removed from Kleopatra
• FormTextInput -> private, removed from Kleopatra
• KeyAlgo -> private, removed from Kleopatra
• NameAndEmailWidget -> private, keep in Kleopatra for the AddSubKeyDialog