[keycloak-user] Extending KeyCloak

Hi, I'm wondering is it possible to extend KeyCloak the following way: 1) add custom entity type (ex., hardware token); 2) provide custom GUI to manage that entities; 3) define custom authentication mechanism (say, OATH HOTP). So, is this possible with current KeyCloak? Does it provide any plugin- like architecture, like, for example, Atlassian Crowd? Thx