deprecate importing individual core modules (#205)

Author: barronalex

MAINTENANCE.md

@@ -106,7 +106,6 @@ dependencies: [.product(name: "MLX", package: "mlx-swift"),
 ```
 import MLXNN
 @testable import MLXOptimizers
-import MLXFFT
 ```
 
 11. Update tests as needed

Source/MLX/Documentation.docc/MLX.md

@@ -36,12 +36,8 @@ are the CPU and GPU.
 ## Other MLX Packages
 
 - [MLX](mlx)
-- [MLXRandom](mlxrandom)
 - [MLXNN](mlxnn)
 - [MLXOptimizers](mlxoptimizers)
-- [MLXFFT](mlxfft)
-- [MLXLinalg](mlxlinalg)
-- [MLXFast](mlxfast)
 
 - [Python `mlx`](https://ml-explore.github.io/mlx/build/html/index.html)