feat: allow full tensorflow usage if available

[mikejgray]

closes #159

[mikejgray]

Hey @dscripka , please let me know if you want any changes on this PR. Happy to adjust it to meet your requirements!

[dscripka]

@mikejgray thanks for the follow-up. Could youadjust the logic so that it only imports from the full tensorflow package if it is both installed and the tflite package is not installed? This happens implicitly right now with the try except block, but it might be a bit more clear by using something like https://docs.python.org/3/library/importlib.html#importlib.util.find_spec to verify the conditions precisely.

[mikejgray]

@dscripka

❯ python
Python 3.12.5 (main, Aug 13 2024, 09:22:07) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import openwakeword
>>> from openwakeword.model import Model
>>> Model()
WARNING:root:Tried to import the tflite runtime, but it was not found. Using tensorflow instead.
INFO: Created TensorFlow Lite XNNPACK delegate for CPU.
>>> import tflite_runtime.interpreter as tflite
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'tflite_runtime'
>>> exit()
❯ pip list | grep tensor
tensorboard               2.18.0
tensorboard-data-server   0.7.2
tensorflow                2.18.0
❯ python
Python 3.12.5 (main, Aug 13 2024, 09:22:07) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from openwakeword.utils import AudioFeatures
>>> x=AudioFeatures(inference_framework="tflite")
WARNING:root:Tried to import the tflite runtime, but it was not found. Using tensorflow instead.
INFO: Created TensorFlow Lite XNNPACK delegate for CPU.