We are renaming files in the pythonic API to make it look less like it is somehow part of z3 (but still acknowledge that we took code from z3Py properly). This PR follows the change in cvc5/cvc5_pythonic_api#80.
This PR fixes a few issues in the documentation, mostly about examples that were not included where they should be.
Improve java documentation: add QuickStart and a java API overview.
