Add automatic generated fortran support for setting and returning contexts

Major cleanup of the code for setting and returning application (previously called user) contexts
- PetscCtx ctx is now t

Add automatic generated fortran support for setting and returning contexts

Major cleanup of the code for setting and returning application (previously called user) contexts
- PetscCtx ctx is now the standard for passing in contexts
- PetscCtxRt ctx is the standard for passing out contexts, including context destroy routines based on PetscCtxDestroyFn

Both of these are typedef to void*

Also removed most use of user and userctx for context arguments now consistently named ctx

Improved documentation on PetscCtx and PetscCtxRt and on how to use contexts (including getting them) from Fortran

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Improve the propagation of function domain error handling in SNES, especially in the line search routines.

Due to the object layering of SNESLineSearch under SNES there is some code duplication incl

Improve the propagation of function domain error handling in SNES, especially in the line search routines.

Due to the object layering of SNESLineSearch under SNES there is some code duplication include both SNESLineSearchReason and SNESConvergedReason and SNESCheckFunctionNorm() and SNESLineSearchCheckFunctionNorm() and Jacobian friends

Reported-by: david.knezevic@akselos.com

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checkbadSource: enforce proper style in makefiles

Fix the definition of PetscErrorCodeFn; this reverts API change in !8615

Co-authored-by: Pierre Jolivet <pierre@joliv.et>
Reported-by: Lisandro Dalcin <dalcinl@gmail.com>

Introduce PetscFortranCallbackFn to be used instead of PetscVoidFn for Fortran callback functions

Also fix incorrect use of SNESFunctionFn and SNESJacobianFn in SNES Fortran manual stub

Change use of void (*)(void) and void (**)(void) in the PETSc API to PetscVoidFn * and PetscVoidFn ** or PetscErrorCodeFn * or PetscErrorCodeFn **