oversensitive deferred revenue account validation

Tasks:

1. When creating contribution / payment associated with creating in backoffice a contribution, membership or event registration, change validation that currently requires a deferred revenue relation for all financial_types (either 1 in simple case, or each line item's in case a price set is being used) if there is a revenue recognition date after the current month, either because the field is set, the membership would extend the current month, or the event start date is after the current month. Instead, if the / a financial type does not have the relation defined:
1.1 For explicitly entered Revenue Recognition Date for contribution with single line item, fail validation with message 'Revenue Recognition Date cannot be processed unless there is a Deferred Revenue account setup for the Financial Type. Please remove Revenue Recognition Date, select a different Financial Type with a Deferred Revenue account setup for it, or setup a Deferred Revenue account for this Financial Type.'
1.2 For other cases where there is no deferred revenue account but there is an explicit or implicit revenue recognition date (eg memberships lasting more than a month, event registration with a start date after the end of current month, contribution lines in membership or event price sets, multiline contribution), pass validation but display following informational warning message on appropriate line item(s) before saving: 'Note: Revenue for this item will not be deferred as the financial type does not have a deferred revenue account setup for it. If you want the revenue to be deferred, please select a different Financial Type with a Deferred Revenue account setup for it, or setup a Deferred Revenue account for this Financial Type.' Dialog should have Cancel and Save buttons.

2.1. On Administer > CiviMember > Membership Types, create/edit a particular membership type, if the membership is for more than 1 month and the financial type does not have a deferred revenue account relation configured, pass validation but display the following informational warning message before saving: 'Note: Revenue for these types of memberships will not be deferred as the financial type does not have a deferred revenue account setup for it. If you want the revenue to be deferred, please select a different Financial Type with a Deferred Revenue account setup for it, or setup a Deferred Revenue account for this Financial Type.' Dialog should have Cancel and Save buttons.
2.2 When processing a front office membership purchase, only record deferred revenue transactions for a line item if a) there is a deferred account relation for its financial type AND b) deferred revenue is enabled.

3. On Events > Manage Events, add or configure a specific event, Fees tab, if the financial type does not have a deferred revenue account relation configured, pass validation but display following informational warning message on appropriate line item(s) before saving: 'Note: Revenue for this event registration will not be deferred as the financial type does not have a deferred revenue account setup for it. If you want the revenue to be deferred, please select a different Financial Type with a Deferred Revenue account setup for it, or setup a Deferred Revenue account for this Financial Type.' Dialog should have Cancel and Save buttons. Use a similar dialog when an attempt is made to save a price field or price field option for an events priceset with a financial type without a deferred revenue account configured for it.
3.1 When processing a front office event registration, only record deferred revenue transactions for a line item if a) there is a deferred account relation for its financial type AND b) deferred revenue is enabled.