Provide default implementation for purging Acquia Platform CDN from invalidation/revalidation events.

[fiasco]

Describe the solution you'd like
When static content is regenerated, we should be able to notify Acquia Platform CDN and purge corresponding URLs after they've been regenerated.

[joshirohit100]

Noticed that next drupal module also has next_extra (experimetal though) that allows to re-validate in nextjs app - https://next-drupal.org/guides/on-demand-revalidation

I think in same process we can utilise to purge the cache from CDN as well while re-validating from nextjs

[lauriii]

The purging in next-drupal is unfortunately based on paths. We could potentially integrate that with Acquia Purge but I'm not sure we should. At the moment, Acquia Purge only queues purges for tags based invalidations which is the only solution that can work consistently out-of-the-box. The path based invalidation will always require developer intervention since it is very hard for us to predict which paths should be invalidated.

Ideally we could resolve this after #17 is done.