ENH: IdentifySample - use algorithm class and add cancel and message feedback

[imikejackson]

Algorithm Updates

• Moved actual algorithm code to the Algorithm class.

Unit Testing

• Added "Slice-by-slice execution" test with 3 SECTIONs (XY, XZ, YZ planes) using synthetic 5x5x3 geometry with a connected block and
  disconnected voxel
  • Added "UInt8 mask type" test using a 5x5x5 geometry with UInt8Array, testing both sample identification and hole filling