ENH: cyclicAMI: extend faceAreaWeight to filter. See #2378

Summary

See #2378 (closed).

Attached is a hack of tutorials/basic/laplacianFoam/implicitAMI with the two blocks separated slightly and the AMI changed into an ACMI. In the blockMeshDict the search-distance is tuned to find only overlaps where the faces are close together (closer than 5e-3):

    AMI1
    {
        type            cyclicACMI;
        maxDistance2    25e-6;
        neighbourPatch  AMI2;
        transform       noOrdering;
        nonOverlapPatch AMI1_blockage;
        ..
    }

Running checkMesh -allGeometry will write postProcessing mask file showing that the overlap is 100% where the faces are close and 0 where they are further away.

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