QoL: Better update for absolute grid blueprints

[Rodir]

TL;DR
Automatically adjust grid offsets when updating a blueprint

What?
When updating contents for a blueprint in absolute grid mode, adjust offsets automatically so that blueprint is aligned with source

Why?
For convenience, so we dont need to "recalibrate" the offsets and can use the updated blueprint right away

There have been similar suggestions:
viewtopic.php?p=700726
viewtopic.php?p=528518
but doing this auto-adjust on a update operation should make implementation easier, as we dont need a new input or UI elements