Adding reflecting fluxes to Solar load radiation model.
Adding functionality to the boundary radiation models and new
place holder for basic wall types such as transparent, opaqueDiffusive,
opaqueReflective,etc.
Changing radiation wall models to run time selectable.
Adding multi-band capabilities to VF model and improving the set up
for using solar loads in VF and fvDOM radiation models.

- localize some functionality, std::array for digest internals.
  Additional append sub-string methods, pass-through write of digest
  etc.

- only apply component-wise transformCoupleField for non-scalar types

- amalgamate dlSym() and dlSymFound() into a single dlSymFind() backend
  with optional 'required' argument. This makes it possible to
  query and assign at once.

- previously would have different SHA1 depending on whether the
  string was a C-string, a C++-string or if the SHA1 was calculated
  directly or via the OSHA1stream.

    - SHA1("string")
    - OSHA1stream << "string";
    - OSHA1stream << string("string");

  By avoiding string quoting on output, they now all deliver the same
  result. This also means that the following will no longer change the SHA1
  content, since it does not add anything:

    osha<< string() << string() << string() << string();

  This would have previously add a pair of double quotes each time!

- failed when nAlphaSubCycles > 1 and nOuterCorrectors > 1.
  Fixed thanks to Henning Scheufler (DLR Bremen).

- Eg, with surface writers now in surfMesh, there are fewer libraries
  depending on conversion and sampling.

COMP: regularize linkage ordering and avoid some implicit linkage (#1238)

- avoids unnecessary cyclic dependency

- change internal naming from 'EXE_EXT' to 'EXT_EXE' for symmetry with
  'EXT_SO'

- continuation of commit 0e7954c2

ENH: downgrade abort() to exit() in some places (#1238)

Feature indirect lists

See merge request OpenFOAM-plus!253

See merge request OpenFOAM-plus!254

- now also track if the cellSet or cellZone has changed on point
  motion.

- also available as equal() member function

- make I/O operators global (non-member)

Patch contributed by Gavin Ridley.

- in case of cell overlapping a patch : set cell to hole always
- in case of cell changing from hole to calculated: set to hole
  and continue. Do so before 'flood filling' holes.
Patch supplied by Nicolas Edh.

- unnecessary. Can deduce labelRange from the pair of labels.
  These are all the same:

      list[labelRange(18,3)] = 100;
      list[labelRange{18,3}] = 100;
      list[{18,3}] = 100;

  Removing the run-time handling of std::initializer_list in favour of
  compile-time deduction allows the future use of sliceRange as well.
  Eg,

     list[sliceRange{18,3,2}] = 100;
     list[{18,3,2}] = 100;