Aside from some basic refactoring, this commit allows the
`local_useless_inc_subtensor` rewrite to handle more increment zero cases.

`aesara.as_symbolic` is a new function that converts all eligible objects to
`Variable`s.  Unlike `aesara.tensor.as_tensor_variable`, `as_symbolic` will
convert `None`s and `slice`s, or any other types that have equivalent Aesara `Type`s.

Fixes https://github.com/aesara-devs/aesara/issues/733
Clean up tests and config variable cache_optimizations

Not creating a temporary list will enable early exit of all and any.
Faster to create tuple than list contaning constants.
Removed duplicated definition of method.

versioneer must be rerun to support Python 3.11. At the same time, the support
for Python 3.6 was further reduced and also some odd Python 2.7-leftovers removed.

Closes #703.

(I've searched and these are the ones I found.)

In addition, the value is printed (and sometimes the data type).

There was a direct access to a NumPy configuration which was
removed in 1.22. This PR removes the special handling and rely
on accessing the configuration in a controlled way to avoid later
issues.