Adjust "placeable" area in osu! editor to support same limits as ranking criteria (at least)

[peppy]

Apparently it is considered "ok" to place hitobjects slightly leaving the standard playfield grid, according to the ranking criteria. We probably need to support this in some way, whether that means extending the playfield horizontally, or adding an overflow/extended area to the editor which is clearly marked but still allows placement.

Discussed in #16572

^{Originally posted by MkGuh January 23, 2022}
When you right click a slider to finish creating it, and is off the grid, it won't finish.

https://mkguh.s-ul.eu/k5kPtPLE.mkv - video showing the issue

[cihe13375]

It probably worths to mention that in some cases (namely circles with CS<=2 and y=384) hitobjects can be offscreen even if they're perfectly in the current placeable area (both stable and lazer). I think this can be addressed too if we want to adjust the placeable area, maybe automatically move upward the "bottom line" in the editor if small CS (large circles) are used