Transducers (#601)

This commit introduces transducers with specific transducing arities for several builtin higher-order functions as well as transducer support with `into`, `sequence`, and `eduction`. Additionally, we introduce the concept of `reduced` values, which are sentinel wrappers that terminate reduction early for all reducing and transducing processes.

Author: chrisrink10

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  * Added `lazy-cat` function for lazily concatenating sequences (#588)
  * Added support for writing EDN strings from `basilisp.edn` (#600)
  * Added a persistent queue data type (#606)
+ * Added support for transducers (#601)
 
 ### Changed
  * Moved `basilisp.lang.runtime.to_seq` to `basilisp.lang.seq` so it can be used within that module and by `basilisp.lang.runtime` without circular import (#588)