Fetch data directly from pyRAT's api

[K-Meech]

Description

What is this PR

• Bug fix
• Addition of a new feature
• Other

Why is this PR needed?
So far, we have analysed csv files of historical exported data. Ideally, we could fetch this data directly from a pyRAT instance via their REST api.

What does this PR do?

• adds a new module to fetch data directly from the pyRAT api
• This expects PYRAT_URL, PYRAT_CLIENT_TOKEN and PYRAT_USER_TOKEN to be set as environment variables with the relevant values. (this means it can connect to any pyRAT instance, as long as the correct values are set)
• Adds tests using mock pyRAT response data (all added as .json files to the GIN repo). I'm using mock responses so we are never accessing real data or the real pyRAT server during the tests.
• I added a general pooch_data_path function (replacing the previous fixtures for each test dataset), so that any dataset can easily be fetched via name. This reduces the number of lines of code needed to manage this, especially now we have more datasets on GIN.

References

Closes #4

How has this PR been tested?

Tests have been added for all new functionality

Is this a breaking change?

No

Does this PR require an update to the documentation?

Relevant docstrings have been updated

Checklist:

• The code has been tested locally
• Tests have been added to cover all new functionality
• The documentation has been updated to reflect any changes
• The code has been formatted with pre-commit

[adamltyson]

All looks sensible to me. My only suggestion would be to refactor in such a way that it's a bit easier to add support for other colony management systems in the future. Something like oscar/colony_management/pyrat?

[K-Meech]

Thanks @adamltyson - good point! I've made that change now, so I'll go ahead and merge.