Port Reduction module to Java

[aman-dureja]

https://github.com/CategoricalData/hydra/blob/main/hydra-haskell/src/main/haskell/Hydra/Reduction.hs

[joshsh]

A simplified betaReduceTerm function is sufficient for now... just enough to evaluate application terms for the test suite

[joshsh]

This is largely done, in that an analogous term reduction function exists in Haskell and Java (note that the new and superior function was ported from Java to Haskell rather than the other way around). Leaving the issue open, as there are a few smaller pieces of code, such as eta reduction, which are not yet migrated.