Multi-file config for the Super Graph service

[dosco]

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What would you like to be added:

Currently config uses one file per environment (eg. dev, staging, prod, etc) we should move to a multi-file config where we have one folder per environment and config values can be split across multiple files within this folder.

Why is this needed:

For setups where there are a large number of tables and each requires its own role config, etc a single file might not be easy to manage. It might be more useful to split table-role config across several files one per table.