egui_extras::Table improvements (#2369)

* Use simple `ui.interact` for the resize line

* Introduce TableReizeState

* Simplify some code

* Add striped options to table demo

* Auto-size table columns by double-clicking the resize line

* Table: add option to auto-size the columns

* Table: don't let column width gets too small, unless clipping is on

* egui_extras: always use serde

Otherwise using `get_persisted` etc is impossible,
and working around that tedious.

* Avoid clipping last column in a resizable table

* Some better naming

* Table: Use new `Column` for setting column sizes and properties

Also make `clip` a per-column property

* All Table:s store state for auto-sizing purposes

* Customize each column wether or not it is resizable

* fix some auto-sizing bugs

* Fix shrinkage of adaptive column content

* Rename `scroll` to `vscroll` for clarity

* Add Table::scroll_to_row

* scroll_to_row takes alignment

* Fix bug in table sizing

* Strip: turn clipping OFF by default, because it is dangerous and sucks

* Add TableBody::mac_rect helper

* Table: add options to control the scroll area height.

* Docstring fixes

* Cleanup

crates/egui_extras/src/datepicker/popup.rs

@@ -1,10 +1,12 @@
-use super::{button::DatePickerButtonState, month_data};
-use crate::{Size, StripBuilder, TableBuilder};
 use chrono::{Date, Datelike, NaiveDate, Utc, Weekday};
+
 use egui::{Align, Button, Color32, ComboBox, Direction, Id, Layout, RichText, Ui, Vec2};
 
-#[derive(Default, Clone)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+use super::{button::DatePickerButtonState, month_data};
+
+use crate::{Column, Size, StripBuilder, TableBuilder};
+
+#[derive(Default, Clone, serde::Deserialize, serde::Serialize)]
 struct DatePickerPopupState {
     year: i32,
     month: u32,
@@ -243,9 +245,8 @@ impl<'a> DatePickerPopup<'a> {
                     strip.cell(|ui| {
                         ui.spacing_mut().item_spacing = Vec2::new(1.0, 2.0);
                         TableBuilder::new(ui)
-                            .scroll(false)
-                            .clip(false)
-                            .columns(Size::remainder(), if self.calendar_week { 8 } else { 7 })
+                            .vscroll(false)
+                            .columns(Column::remainder(), if self.calendar_week { 8 } else { 7 })
                             .header(height, |mut header| {
                                 if self.calendar_week {
                                     header.col(|ui| {