add read api calls + tests

[peterdudfield]

Pull Request

Description

• add two read function for api calls

This is needed for https://github.com/openclimatefix/uk-analysis-dashboard

How Has This Been Tested?

CI tests + new tests

• [x] Yes

Checklist:

• [x] My code follows OCF's coding style guidelines
• [x] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have checked my code and corrected any misspellings

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (e4012fb) 95.29% compared to head (459a790) 95.30%. Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #253 +/- ## ========================================== + Coverage 95.29% 95.30% +0.01% ========================================== Files 27 27 Lines 1741 1748 +7 ========================================== + Hits 1659 1666 +7 Misses 82 82 ```

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