Limit battery storage duration

[atpham88]

Summary

This PR adds user-input option to limit the hour duration for battery storage.

Implementation notes

Changes in this PR to add this option:

1. electric_storage.jl: added a max_duration_hours input, default as a big number - 100,000 (hours), and min_duration_hours, default is 0 (hour). This defaults can be changed in ["ElectricStorage"]["max_duration_hours"] and ["ElectricStorage"]["min_duration_hours"].
2. storage_constraints.jl: Add a constraint to limit battery energy capacity <= battery power rating * max_duration_hours and battery energy capacity >= battery power rating * min_duration_hours.
3. runtests.jl: Add "Storage Duration" test.

[adfarth]

@atpham88 I changed the new input name from battery_hours to max_duration_hours to indicate that it's an upper bound and not fixing the duration to a certain hours.

Could you:

• Update the CHANGELOG file with a description of these changes
• Make sure all highs tests pass (they're running now)
• Make sure all xpress tests pass by running these locally (I can show how to do this if needed!)

[adfarth]

@atpham88 I pushed a few minor changes. Before I approve, could you please:

• Add a test to runtests.jl to test this capability, for both electric_storage and thermal_storage?
• Update the PR description to indicate that this adds the duration inputs for thermal_storage as well, and reflect the defaults in the code (it still says 30 hours above, which is maybe what you started with but have since updated the max duration)

[adfarth]

@atpham88 Looks good! Feel free to merge into develop