Refactor upgrade detection and maintenance tasks (#4127)

* Refactor upgrade detection and maintenance tasks

There needs to be a process for detecting when a full upgrade is necessary versus only a db upgrade. 

1. Update main tasks to run general upgrade process that  runs either full upgrade or partial db upgrade
2. Update maintenance check to check for general upgrade needed status
3. Add full full_upgrade_needed  variable will define if a full upgrade is necessary

* Update magento 2 docs.

* Cleanup code.

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Co-authored-by: Carlos Reynosa <[email protected]>

Author: carlos-reynosa