- 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 !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 !231

- Global functions are unary or combining binary functions, which are
  defined in MinMax.H (MinMaxOps.H).

  There are also global reduction functions (gMinMax, gMinMaxMag)
  as well as supporting 'Op' classes:

  - minMaxOp, minMaxEqOp, minMaxMagOp, minMaxMagEqOp

  Since the result of the functions represents a content reduction
  into a single MinMax<T> value (a min/max pair), field operations
  returning a field simply do not make sense.

- Implemented for lists, fields, field-fields, DimensionedField,
  GeometricField (parallel reducing, with boundaries).

- Since the minMax evaluates during its operation, this makes it more
  efficient for cases where both min/max values are required since it
  avoids looping twice through the data.

  * Changed GeometricField writeMinMax accordingly.

ENH: clip as field function

- clipping provides a more efficient, single-pass operation to apply
  lower/upper limits on single or multiple values.

  Examples,

    scalarMinMax limiter(0, 1);

    limiter.clip(value)

       -> returns a const-ref to the value if within the range, or else
          returns the appropriate lower/upper limit

    limiter.inplaceClip(value)

       -> Modifies the value if necessary to be within lower/upper limit

  Function calls

    clip(value, limiter)

       -> returns a copy after applying lower/upper limit

    clip(values, limiter)

       -> returns a tmp<Field> of clipped values

- 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.

- assignment operators return a value, for consistency with bool.

- partial revert of DEFAULT_TRUE, DEFAULT_FALSE, to reduce complexity.