[Linalg] Introduce ConvMatchBuilder + refactor Conv matchers

-- This commit is a follow-up and third in the series of adding
   matchers for conv/pool ops. Refer: llvm#163724
-- It introduces ConvMatchBuilder class in order to reduce the
   repetitive code across Conv1D/2D/3D/Depthwise/Pooling variants.
-- Refer to [Conv2D thread](llvm#168362 (comment)) for further context.

Signed-off-by: Abhishek Varma <[email protected]>

Author: Abhishek-Varma