Consolidate and update examples

[rsetaluri]

• Move https://github.com/leonardt/magma_riscv_mini to main repo
• Move https://github.com/leonardt/magma_examples to main repo
• Turn on MLIR testing against all examples by default (e.g.

  magma/tests/test_backend/test_mlir/test_utils.py

  Lines 205 to 224 in 2edf15c

  	@functools.lru_cache()
  	def get_magma_examples(
  	skips=_MAGMA_EXAMPLES_TO_SKIP) -> List[DefineCircuitKind]:
  	try:
  	import magma_examples
  	except Exception as e:
  	return []
  	path = magma_examples.__path__
  	py_filenames = glob.glob(f"{path._path[0]}/*.py")
  	ckts = []
  	for py_filename in py_filenames:
  	py_module_name = py_filename.split("/")[-1].split(".")[0]
  	if py_module_name in skips:
  	continue
  	full_name = f"magma_examples.{py_module_name}"
  	py_module = importlib.import_module(full_name)
  	ckts += list(filter(
  	lambda v: isinstance(v, DefineCircuitKind),
  	(getattr(py_module, k) for k in dir(py_module))))
  	return ckts

  )
• Update existing examples (e.g. https://github.com/phanrahan/magma/blob/master/examples/fifo.py is out of date)
• Add CI to test all examples