make solver parameters declared in the generated files static

[kostas-l]

As a forces user

I want the solver parameters that are declared in the generated files for the interfaces as well as the main solver, especially the local variables, to be declared static

so that I don't receive runtime issues due to a stack overflow

NOTES

• In the main solver file we can also use the thread local functionality so that the main solver file can be safely compiled and packaged along with the internal solvers into a single library