add option to load sat 15 min data if no satellite data is available

[peterdudfield]

Pull Request

Description

IF there is no 5 mins sat data, try to load 15 min data

Fixes #685

How Has This Been Tested?

normal unittests

• [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
• [ ] 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-commenter]

Codecov Report

Merging #686 (b4d780f) into main (1c90092) will increase coverage by 0.01%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #686      +/-   ##
==========================================
+ Coverage   93.29%   93.31%   +0.01%     
==========================================
  Files          48       48              
  Lines        3357     3365       +8     
==========================================
+ Hits         3132     3140       +8     
  Misses        225      225              

Impacted Files	Coverage Δ
...et/data_sources/satellite/satellite_data_source.py	94.08% <100.00%> (+0.29%)	:arrow_up:

:mega: Codecov can now indicate which changes are the most critical in Pull Requests. Learn more