[mlir][Linalg][Vector] Add forwarding patterns between linalg.copy and vector.transfer

This revision adds custom rewrites for patterns that arise during linalg structured
ops vectorization. These patterns allow the composition of linalg promotion,
vectorization and removal of redundant copies.

The patterns are voluntarily limited and restrictive atm.
More robust behavior will be implemented once more powerful side effect modeling and analyses are available on view/subview.

On the transfer_read side, the following pattern is rewritten:
```
   %alloc = ...
   [optional] %view = std.view %alloc ...
   %subView = subview %allocOrView ...
   [optional] linalg.fill(%allocOrView, %cst) ...
   ...
   linalg.copy(%in, %subView) ...
   vector.transfer_read %allocOrView[...], %cst ...
```
into
```
   [unchanged] %alloc = ...
   [unchanged] [optional] %view = std.view %alloc ...
   [unchanged] [unchanged] %subView = subview %allocOrView ...
   ...
   vector.transfer_read %in[...], %cst ...
```

On the transfer_write side, the following pattern is rewriten:
```
   %alloc = ...
   [optional] %view = std.view %alloc ...
   %subView = subview %allocOrView...
   ...
   vector.transfer_write %..., %allocOrView[...]
   linalg.copy(%subView, %out)
```

Differential Revision: https://reviews.llvm.org/D80728

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