Summary of Changes

In order to do things like be able to set up a cron job to run the session metadata purge operation (versus having it arbitrarily run on select HTTP requests based on very subjective criteria), we need to extract the processes performing CRUD operations on this data to a separate service class. This PR accomplishes just that.

A new MetadataManager class is created which is now used for creating metadata records as needed and deleting selected records. This class is purposefully declared final and annotated @internal as this should not be an extension integration point and its definition will change when merged to the 4.0 branch. For now it is only used by the application class to do the same operations that are already happening, but as an example a new CLI script and global config option can be added so that users can turn off the cleanup operation in web requests and fully manage this in cron jobs.

Testing Instructions

For now, nothing should change. So, session metadata should still be written when a new session created, and the delete operation triggered based on the changed criteria of 3.8.4 (a second on a divisor of 5 when non-database handlers are in use).