Create an efficient `all_subtypes` function

[hunterhector]

Is your feature request related to a problem? Please describe. Getting all subtypes of a certain type in the data store is used in multiple places (1, 2), but could be implemented inefficiently and can be wrong. We should create one single function for this.

Describe the solution you'd like The solution should consider:

1. Caching results so get subtype won't be doing the same thing repeatedly
2. Make sure the subtype orders and everything is the same across different calls (sorting the output)

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context

• This is part of the data efficiency project
• This PR should be made to the master branch.
• After the data tuple class is finished, we may switch to a new branch for integration.

[hunterhector]

@J007X could be a source for efficiency