Form Integrations: Build migration routines from old methods.

[danieliser]

We need to migrate away from the settings available in the form editors. That isn't sustainable long term and leads to needless complexity compared to the new methods.

We need to

• [ ] Deprecate all code related to those functionalities.
• [ ] Add migration routine for each provider to move options into popup settings.
• [ ] Add notice for any settings that cannot be migrated.

Migration Routine

1. Loop over each form.
2. Pull closepopup, closepopup_delay, openpopup & openpopup_id settings from form.
3. If openpopup: add Form Submission trigger to the popup with ID matching openpopup_id. May need to add delay to Form Submission trigger equal to that of the closepopup_delay.
4. If closepopup: Search all popups for those that contain this form, for each found setclose_on_form_submission to 1, set close_on_form_submission_delay to closepopup_delay.
5. Remove all form settings/actions.
6. Set option to tell our code that this migration has been proccessed.
7. Disable loading of old settings screens in form editors based on option saved in 6 above.

Form Plugins

• [ ] Ninja Forms
• [ ] Gravity Forms
• [ ] Contact Form 7