Infer "Skip", "Run", & "Only" and remove the Transform step from the UI
Context:
- https://gitlab.com/meltano/meltano/merge_requests/1095#note_238123522
- https://gitlab.com/meltano/meltano/merge_requests/1095#note_238525311
### Todo
- [x] remove transform step from UI
- [x] properly advance past transform step
- [x] ensure transform selection defaults/saves as expected
- [x] confirm best inference plan ("Run" and let BE determine if "Skip" where "Only" is CLI-only?)
issue