Allow custom project definitions

[AndrewNolte]

I think it was be nice to customize the project descriptor format, rather than just sticking to the standard ones like EDAM and vunit. For example, settings up a configuration like this

"teros.projects.lsproj" : "findprojects.sh" -> outputs project -> file backing name "teros.projects.lsconf" : "findconfigs.sh" -> outputs project -> list[configs] where configs are parameterizations of the project

And having the project structure tab use these to find projects and configs. I actually don't see a sort of config tab like this, how is this achieved currently? I'm assuming edalize has something like this for configs, or would each config be a different project currently?