Drop `spark` package, or move it to the TUR.

[TomJo2000]

spark has not seen any signs of life in 7+ years. https://github.com/holman/spark

On top of that it is 103 line Bash script, with no patches required to make it work on Termux.

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As this does not meet current packaging guidelines, I propose we drop the package or move it to the TUR if so desired.

I'm not sure if we should contact upstream about the decision beforehand. The author seems to be active, but as mentioned the project has not seen any activity in 7 years, and I don't want to be a nuisance about an abandoned project.