More functor integral postprocessors

[GiudGiud]

@lynnmunday these two PPs should be usable for variable * function integral with:
functor = variable
prefactor = function

Refs #16099

[lindsayad]

Oh @lynnmunday is going to dive into the beautiful world of functors?

[moosebuild]

Job Documentation on d6e983c wanted to post the following:

View the site here

This comment will be updated on new commits.

[moosebuild]

Job Coverage on d6e983c wanted to post the following:

Framework coverage

	7e9638	#22525 d6e983
	Total	Total	+/-	New
Rate	84.23%	84.23%	+0.00%	85.71%
Hits	80283	80301	+18	30
Misses	15028	15031	+3	5

Diff coverage report

Full coverage report

Modules coverage

Coverage did not change

Full coverage reports

Reports

• framework
• chemical_reactions
• combined
• contact
• electromagnetics
• external_petsc_solver
• fluid_properties
• fsi
• functional_expansion_tools
• geochemistry
• heat_conduction
• level_set
• misc
• navier_stokes
• peridynamics
• phase_field
• porous_flow
• ray_tracing
• rdg
• reactor
• richards
• scalar_transport
• solid_properties
• stochastic_tools
• tensor_mechanics
• thermal_hydraulics
• xfem

Warnings

• framework new line coverage rate 85.71% is less than the suggested 90.0%

This comment will be updated on new commits.

[lynnmunday]

Oh @lynnmunday is going to dive into the beautiful world of functors?
I have some googling to do!

[GiudGiud]

https://mooseframework.inl.gov/moose/syntax/Materials/#a325f876-c5a8-49dc-b34f-0f96cb0fbec5
https://mooseframework.inl.gov/docs/doxygen/moose/classMoose_1_1FunctorBase.html

might be the only docs on functors