feat(mat-select): add smart panel width based on trigger and largest option size

[Harpush]

Feature Description

Currently panelWidth can be one of three:

1. Trigger width
2. Largest option width
3. Custom provided width in numbers

What I am missing is - minimum width as trigger width and grow until max option size (if needed)

Use Case

When having dynamic options texts sometimes they might be larger than trigger width and I want the largest option behavior.
Sometimes they are smaller than trigger width and I want the trigger width behavior to avoid really small select panels.
Which means I actually need: min panel width = trigger width with potential grow (not shrink!) to the largest option width.

Can be with a new panelWidth option or even minPanelWidth input (can have a complimenting maxPanelWidth too for completeness)

[Prinzhorn]

I was about to open a documentation issue about this, because panelWidth is documented as:

Width of the panel. If set to auto, the panel will match the trigger width. If set to null or an empty string, the panel will grow to match the longest option's text.

which is not correct. It will grow or shrink. The shrinking behavior seems bad for ux and also looks bad. Maybe instead of making this a new option, the current one should be fixed to match the documentation (which was likely also the intent).