Sheet width can't be changed #26

Summary

SheetContent is always min(384, 75% of the window) wide (shadcn's w-3/4 sm:max-w-sm), with no property to change it. Sheets that hold a table or a form need more room.

Proposal

Add MaxPanelWidth (default 384) or Size presets (Sm, Md, Lg, Xl, TwoXl = 384 / 448 / 512 / 576 / 672) to the MAUI and Avalonia sheets, and the same for Drawer's height if it has the same limit.