Automatically choose origin (along with anchor) to make skin editor placement easier for users

[peppy]

Users still don't really understand anchors and origins (and I kinda don't blame them – as a concept it takes a bit of brain power to get right), so let's choose for them in most cases and take the guesswork out of it.

https://github.com/ppy/osu/assets/191335/88ff78ec-0dd3-4ccc-ae65-cd2c6545a0a8