fv::convectionScheme does not accept all schemes

The reacting solvers like the combustion solvers, Lagrangian solvers or heat transfer solvers use a fv::convectionScheme object for the convection term of species mass fraction and energy instead of fvm::div:

https://develop.openfoam.com/search?utf8=%E2%9C%93&search=fv%3A%3AconvectionScheme&group_id=&project_id=5&search_code=true&repository_ref=develop#L1

This prevents the use of certain discretization schemes like "linear". For example, in the $FOAM_TUTORIALS/combustion/reactingFoam/laminar/counterFlowFlame2D case, replace

div(phi,Yi_h) Gauss limitedLinear 1;

with

div(phi,Yi_h) Gauss linear;

The error will read:

--> FOAM FATAL IO ERROR: Unknown discretisation scheme linear

Valid schemes are :

12 ( Gamma MUSCL Minmod SuperBee limitedCubic limitedLimitedLinear limitedLinear limitedLinear01 multivariateIndependent multivariateSelection upwind vanLeer )

Is this the intended behavior? Having the ability to choose schemes like "linear" or "cubic" might be advantageous for very fine meshes or DNS-like simulations.

## Reattaching the author to the issue ticket: @g3 ##