[Layout] Refactor the shared layout system

[yaoyaoding]

Previously, we use the following layout system for shared tensor:

axes: list[Var]
offset: Expr

where offset is an expression regards the axes.

This PR refactors the layout to a cute-like layout system:

shape: list[int]
mode_shape: list[int]
mode_strides: list[int]
swizzle: Optional[Swizzle]

For example, consider a shape of (64, 32), we can split the first dimension into two sub-dimensions (modes) of size 8 and 8, and the second dimension into two sub-dimensions (modes) of size 16 and 2. The mode shape would be (8, 8, 16, 2). We can have strides for each mode, for example, (256, 2, 16, 1). Then given the indices (i, j), we can compute the indices in the sub-dimensions (i1, i2, j1, j2) where i1 = i // 8, i2 = i % 8, j1 = j // 2, j2 = j % 2. The offset can be computed as:
offset = i1 * 256 + i2 * 2 + j1 * 16 + j2 * 1. To get the final offset in the shared tensor, we can use the formula:
(i, j) => ((i // 8) * 256) + ((i % 8) * 2) + ((j // 2) * 16) + ((j % 2) * 1).