Strip history of the nvda-portable directory

[gnarf]

There were a couple of big zip files committed here before switching to a cleaner approach to distributing these files in PR #8

We should use https://github.com/newren/git-filter-repo/ to clean these files out of the history: git-filter-repo --path nvda-portable --invert-paths should do it.

We should do this at a time when no open PR exist as the result will be a force push back to main - we can preserve old-main for a little bit in case of long term problems, but I don't think there will be any.

[jugglinmike]

GitHub's "checkout" action sensibly defaults to a shallow clone, so the presence of an irrelevant 50-megabyte binary blob won't have a practical impact on CI performance. Persisting the file in the history might be a bit wasteful for folks who clone this repository manually, but I'm not certain that's sufficient motivation to perform this operation. We don't expect this repository to be cloned by many people, after all, and people may one day wish to accurately recreate the repository in its early state

@gnarf does that seem reasonable to you?

[gnarf]

Sure - but I think it's actually 3 or 4 different blobs as a new NVDA dropped and plugin updates etc