Add none indexing for lazyudf/lazyarray

[lshaw8317]

Array API compliance requires None indexing to introduce a new "dummy" axis (as in NumPy). As part of this effort, this PR implements this behaviour for LazyArray objects:

import blosc2
import numpy as np
a = blosc2.ones((10,))
expr = a + 1 
sl = (np.newaxis, slice(3, 8), None)
res = expr[sl]
print(res.shape) # (1, 5, 1)

[FrancescAlted]

LGTM