Integration bgFilters

[korgon]

Snap Templates is going to start with the ability to add middleware and plugins removed. But we must support some basic functionality, so we will have to add ability to opt into "authorized" plugins in Snap Templates. The most important of these plugins will handle the background filters that are currently used for these platform integrations. The changes here should make it easy to add additional plugins as they become necessary. These plugins need to be configurable so that they can meet different use cases.

platform: {
  shopify: { ... },
  bigCommerce: { ... },
  magento2: { ... },
}

In addition to supporting platform specific plugins there are a few plugins that should be for all implementations regardless of platform:

• scroll to top
• store logging (via log.debug)

Additionally, support for providing generic background filters could be provided via script context variables.

[korgon]

Can we refactor middleware functions to be named functions for easier testing / debugging.

[korgon]

Merged into develop.