Refresh pipeline cache on process external modifications

[cristiandonoiu]

This is needed in case a pipeline is changed directly in the DB (without using the provided PipelineStore api) or from another process.
We can use Mongo ChangeStreams.

Sample code and saving of the resumeToken mentioned here:
https://stackoverflow.com/questions/75465217/mongodb-how-to-stop-and-resume-change-stream/75477516#75477516
We do not need to do change data capture so no need to save resumeToken.
Instead, do a full refresh of the cache on every modification on the pipeline collection.