Consolidate and add error handling to loading of trigger params

CRM/Civirules/BAO/CiviRulesRule.php

CRM/Civirules/Delay/DelayBasedOnDateField.php

CRM/Civirules/Form/Rule.php

CRM/Civirules/Trigger.php

CRM/Civirules/Trigger/Post.php

CRM/CivirulesConditions/Form/Form.php

CRM/CivirulesCronTrigger/Activity.php

CRM/CivirulesCronTrigger/EventDate.php

CRM/CivirulesCronTrigger/GroupMembership.php

CRM/CivirulesCronTrigger/HasTag.php

CRM/CivirulesCronTrigger/MembershipEndDate.php

CRM/CivirulesCronTrigger/NextContributionDate.php

CRM/CivirulesPostTrigger/Activity.php

CRM/CivirulesPostTrigger/Event.php

...ulesPostTrigger/RelatedParticipantWhenActivityChanged.php

...lesPostTrigger/RelatedParticipantWhenActivityIsTagged.php

CRM/CivirulesTrigger/Form/Form.php