Reduce amount of macros when compiling ionic models
As pointed out by @aneic and @axel.loewe during the openCARP user meeting, the amount of macros used when generating ionic models (one per target and models) is way too big and clutters the build output and the code. I'm creating this issue just to have a written version of this concern that can be found easily.
It would probably be cleaner to chose targets for all models at once as a finer granularity is probably not needed.
The only good reason for keeping such a fine granularity would be to disable some models for a specific target when there are bugs or issues, but that might not justify it for most cases.
We might also keep both ideas by simplifying the amount of macros used if all models are to be built on the same targets, and keep the finer granularity if wanted.