[change] Move from_string to array_creation_routine module

[forFudan]

It is to partially resolve #110, Item 8.

Move from_string to array_creation_routine module.

Also make a reload of array that accepts string as object.

The unit tests failed for inverse, matmul and solve, not this one.

Example:

import numojo as nm

fn main() raises:
    var A = nm.from_string[DType.int8]("[[[1,2],[3,4]],[[5,6],[7,8]]]")
    var B = nm.from_string[DType.float16]("[[1,2,3,4],[5,6,7,8]]")
    var C = nm.from_string[DType.float32]("[0.1, -2.3, 41.5, 19.29145, -199]")
    var D = nm.from_string[DType.int32]("[0.1, -2.3, 41.5, 19.29145, -199]")

    print(A)
    print(B)
    print(C)
    print(D)

The output goes as follows. Note that the numbers are automatically
casted to the dtype of the NDArray.

[[[     1       2       ]
  [     3       4       ]]
 [[     5       6       ]
  [     7       8       ]]]
3-D array  Shape: [2, 2, 2]  DType: int8

[[      1.0     2.0     3.0     4.0     ]
 [      5.0     6.0     7.0     8.0     ]]
2-D array  Shape: [2, 4]  DType: float16

[       0.10000000149011612     2.2999999523162842      41.5    19.291450500488281      199.0   ]
1-D array  Shape: [5]  DType: float32

[       0       2       41      19      199     ]
1-D array  Shape: [5]  DType: int32

[shivasankarka]

@forFudan shouldn't we use fromstring instead of from_string to keep it same as numpy?

[forFudan]

@forFudan shouldn't we use fromstring instead of from_string to keep it same as numpy?

@shivasankarka You are right! I made the change.