enh: move all dependecies to optional-dependencies rather than defining them within hatch envs

If we use optional dependencies, which is a packaging standard ✨, then we can refer to those groups in the hatch environment as features. This provides more flexibility to users who might not want to use hatch environments and also reduces the complexity of our template. Finally, in the future, if we ever need to move away from Hatch, it will make that process more straightforward too. It's a win-win!! I'll work on this next. My post: *> > * I think we should use optional-dependencies to add things to - and then Hatch can call those dependencies via the features = "groupname" > * Some of our dep groups are missing dependencies now so things don't run out of the box. for example RTD build fails as it's missing some dependencies. > opened this issue here #124 _Originally posted by @lwasser in [#123](https://github.com/pyOpenSci/pyos-package-template/issues/123#issuecomment-3474542709)_