feat(ui5-table): improve default column widths

[DonkeyCo]

Instead of using auto as default width, the table columns will default to 1fr. This allows table columns to equally take the available space.
This ensures the column's default width does not depend on the column content, leading to a more stable experience.

Additional changes:

1. remove max-width
2. defaults: width=undefined (use 1fr internally), min-width: 3rem
3. remove left, right border of row according to design spec
4. add "empty/dummy" space according to design spec
5. adjust padding-left of first column/cell

Fixes #10536
Fixes #11051
Partially fixes #10716

[aborjinik]

as I said we should not try to be smart with the column templates but this continues in this change.
what i expect is having a single width property(1fr by default) for the column, no min/max width and cells have the min-width: 3rem in their css. we document that the cell should not be less than 3rem. With the width property of the column they can make it smaller than 3rem but this is not our problem anymore.

lets discuss on monday again.