Feature object registry search

See merge request OpenFOAM-plus!232

  - objectRegistry search, erase methods
  - clip, minMax
  - function object triggering
  ...

- The findObject() methods are template-typed and used to locate a
  particular Type/name combination.

  Eg,

      volScalarField* ptr = obr.findObject<volScalarField>("xyz");

- The findIOobject() methods are un-typed and use the name only.

  Eg,

      regIOobject* ptr = obr.findIOobject("xyz");

The typed versions will be most commonly used, but the un-typed lookup
can be useful in a templating.

- Simplified findObject* methods to use findIOobject* as the backend.

- similar to what erase() does, but as a mutable operation (#1180)

- replace basicThermo lookupAndCheckout (commit 880c9875) with
  the new objectRegistry::checkOut() method.

- implemented as lazy evaluation with an additional update() method.
  This avoids unnecessary changes until the values are actually
  required.

- apply mesh motion changes for momentum, volFieldValue,
  specieReactionRates function objects

- forwards to the underlying HashTable erase, but frees things owned
  by the registry as well (ie, performs a checkOut)

- also removed some editing cruft from controlDict that should not
  have been there

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480

from e to T. T proved to be more generic solution.

Add minMax and clip field functions

See merge request OpenFOAM-plus!230

STYLE: avoid local variable name masking

- changed ensightOutput from a class solely comprising static methods to
  a namespace and added in sub-namespaces Detail and Serial.

  This makes it easier to "mix-in" functions at different levels.
  Refactored and combined some serial/parallel code where possible.

  The general ensightOutput namespace has now shifted to be in the
  fileFormats lib, while leaving volField outputs in the conversion lib
  and cloud outputs in the lagrangian-intermediate lib.

  The ensightCloud namespace is now simply folded into the new
  ensightOutput namespace.

  These changes clean up some code, reduce fragmentation and
  duplication and removes the previous libconversion dependency for
  sampling.

- use int for ensight nTypes constexpr

Note: issue #1176 is unaffected except for the change in file name:

   ensightOutputTemplates.C -> ensightOutputVolFieldTemplates.C

Function object updates

See merge request OpenFOAM-plus!231

- allows localized extension of functionality

- improved the selection mechanism to include using a bitSet
  cell selection (more efficient and convenient).

  Use templated implementation internally to remove the previous
  reliance on a NullObject.

    Example usage:

    continuityError1
    {
        type        continuityError;
        libs        ("libfieldFunctionObjects.so");
        ...
        writeToFile yes;
        log         yes;
        phi         phi;
    }