Shortable Provider Improvements

[Martin-Molinero]

Expected Behavior

• Document improvements made at https://github.com/QuantConnect/Lean/pull/7579
• Update https://www.quantconnect.com/datasets/us-equities-short-availability & add new IB short availability data set

  Actual Behavior

  N/A

  Checklist

• [x] I have completely filled out this template
• [x] I have confirmed that this issue exists on the current master branch
• [x] I have confirmed that this is not a duplicate issue by searching issues

[AlexCatarino]

The dataset page was updated. Docs updated (https://github.com/QuantConnect/Documentation/commit/65cb25f0ae89a436cfea198eb95812b8e134704b) to reflect new constructor overload for LocalDiskShortableProvider.

TODO: Add H3 for InteractiveBrokersShortableProvider after LocalDiskShortableProvider. Note that InteractiveBrokersShortableProvider -> LocalDiskShortableProvider("interactivebrokers")

We can add an example of extending the InteractiveBrokersBrokerageModel to add InteractiveBrokersShortableProvider.

[AlexCatarino]

Closed by 1aff378