Feature request: add support for Subscription Delays

[michaelbeil]

Is your feature request related to a problem?
Currently, each payment plan cannot have a trial. A customer (ticket 441479) is wanting trials for each payment plan.

Describe the solution you'd like
Add support for Subscription Delays.

[dwanjuki]

Another customer is requesting this feature. (ticket 481210)

[ipokkel]

Another customer is requesting this feature. (ticket 514618)

[andrewlimaza]

Another customer is requesting this feature. (ticket 538320)

[kimcoleman]

This issue would require us to overhaul the way Payment Plans works via JavaScript. We need to keep this discussion open. For now, the best approach would be to not use the Payment Plans Add On and instead use these recipes for replicating the functionality but with distinct levels - each with their own unique trial or subscription delay.

See: https://github.com/strangerstudios/pmpro-snippets-library/blob/dev/checkout/add-select-payment-plan-box-membership-checkout.php