Prevent duplicate queue items from being created

Problem/Motivation

The module currently creates queue items for every published node on every cron. It's likely, and entirely possible, that duplicate queue items are being created.

An example with cron running every hour:
Cron runs. During the queue time not all the items are processed.
Con runs again. Since every published node gets a queue item, some of the items are duplicates.

Proposed resolution

A database solution like Overriding Queues in Drupal 7. Or How Not to Create Duplicate Queue Items is not performant. It takes creating items from seconds to too many minutes to even count.

I'm looking into a solution like the one described in How to check if an item exists in a Queue?

Adding this feature to the module will be a performance boost for the module since duplicate queue items won't exist.

Remaining tasks

1. Add a GoogleAnalyticsCounterProcessor and GoogleAnalyticsCounterProcessorInterface to the module which only creates an item when the same item hasn't already been created.

User interface changes

None

API changes

GoogleAnalyticsCounterProcessor service will be added to the container.

Data model changes

None