epic: street editing good enough to release for basic streets

[kfarr]

ultimate goal: as a user I can take a stroad example and then change in to a safer configuration -->

• ability to change street to another segment type preset
• Use random seed #971
• option to delete a segment and have reflow #975
• insert new segment function via type and/or object #976
• somehow i can move cloned children saved as manual objects #990
• ensure auto-striping works after type change / delete / add #977 - striping
• ensure striping & stencil alignment options work after resizing and justification reflow #980
• insert new segment using drag and drop from bottom panel #988
• editing managed street properties has key properties exposed in custom side panel #978
• editing street segment properties has key properties exposed in custom side panel #979
• (p) as a user placing objects on a street, I then want to move or rotate my street and those objects should follow that rotation #832
• ability to move segment from old index to new index
• ensure undo works for delete, insert, move