[mlir][emitc] Add ArrayType (#83386)

This models a one or multi-dimensional C/C++ array.

The type implements the `ShapedTypeInterface` and prints similar to
memref/tensor:
```
  %arg0: !emitc.array<1xf32>,
  %arg1: !emitc.array<10x20x30xi32>,
  %arg2: !emitc.array<30x!emitc.ptr<i32>>,
  %arg3: !emitc.array<30x!emitc.opaque<"int">>
```

It can be translated to a C array type when used as function parameter
or as `emitc.variable` type.