ENH: code modernization for decompose/reconstruct

- simplify procAddressing read/write

- avoid accessing points in faMeshReconstructor.
  Can rely on the patch meshPoints (labelList), which does not need
  access to a pointField

- report number of points on decomposed mesh.
  Can be useful additional information.
  Additional statistics for finite area decomposition

- provide bundled reconstructAllFields for various reconstructors

- remove reconstructPar checks for very old face addressing
  (from foam2.0 - ie, older than OpenFOAM itself)

- bundle all reading into fieldsDistributor tools,
  where it can be reused by various utilities as required.

- combine decomposition fields as respective fieldsCache
  which eliminates most of the clutter from decomposePar
  and similfies reuse in the future.

STYLE: remove old wordHashSet selection (deprecated in 2018)

BUG: incorrect face flip handling for faMeshReconstructor

- a latent bug which is not yet triggered since the faMesh faces are
  currently only definable on boundary faces (which never flip)