Standarized spector scenario generator #5022

On top of having a combined conifg #4997 we might be able to share the logic for generating the spector tests, this would reduce the eng maintenance of each team and improve contributor/agent experience not having to find many ways to deal with things.
It probably also can be implemented in a more preformant way than all of them right now bringing perf benefit for everyone.

Things to take into account

• might need specific option support for a scenario https://github.com/microsoft/typespec/blob/main/packages/http-client-python/eng/scripts/ci/regenerate-common.ts#L84