BoardCard class Titan compatibility

[batstyx]

• Add titan check and titan abilities used count

• Return false from IsAbletoAttack method if card is titan and still has unused abilities

• Issue #4503

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[batstyx]

This probably needs a silenced check as well, haven't had time to test that yet.

Update: Silence removes TITAN tag, so silenced behaviour is correct as is.

[azeier]

Thanks for yet another fix!