Dataset mappings

[neeleshdodda44]

Hopefully, this a short PR.

Dataset Manager

• Added a method create_dataset_mappings to generate mappings from random UUIDs to dataset folders, and store this in a yaml file called datasets.yaml.
• Added a method bootstrap to decide whether to load the yaml file (if it exists) or call create_dataset_mappings
• Added a method get_mappings that returns the loaded mappings, if they exist.
• Added tests for these new methods.

Tl;dr the implementation mirrors that of the Configuration Manager (I ultimately decided not to just put the mappings in configuration.ini since I thought that would break abstractions).

NOTE: I accidentally committed parts of the first two methods above in a previous PR, please make sure to still review all of each of the methods.

[neeleshdodda44]

@georgymh could you explain why UUID again? Like instead of just using the dataset names or other ways of generating random identifiers?

I have an idea of how to make this smoother, but I'm not sure if it would compromise your original reasons for having identifiers in the first place.

[neeleshdodda44]

So the reason why I ask is because it might be better to use some kind of deterministic encoding (like uuid3/uuid5 and some arbitrary namespace in the docs) so that we don't even need to store the mappings in some file. Obviously not necessary (and there's some drawbacks), but I think it's alternative to consider.

Since I've got two approvals, I'm just going to go ahead and merge.