Editor: Fixed sidebar glitches

[ycw]

The issues:

1. Editor's sidebar not wide enough for language ja , so on first-run, the property tabs will be wrapped:

2. Currently sidebar's width is unrecoverable, so say Japanese users have to resize the sidebar every time the editor restarted (including refresh the page for purging texture input's cache :D)

3. Resizer can be dragged way too far to the right, so for languages fr and ja the property tabs will be wrapped:

resizer.too.far.mp4

4. Resizer can be dragged way too far to the left, so once users release the pointer, the resizer can't be dragged again because it's now out of window:

resizer.is.gone.mp4

This PR:

• Fixed 1 by detecting effective language on first-run, and then set proper width
• Fixed 2 by (re)storing sidebar's width to Config
• Fixed 3 by restricting sidebar's min-width based on editor Settings>Language
• Fixed 4 by setting lower bound of sidebar's width to 10(px) instead of 0(px)

Preview: (open in incognito mode to mimic first-run) https://raw.githack.com/ycw/three.js/editor-sidebar-width-is-user-pref/editor/index.html

[mrdoob]

This is yet more code that needs to be maintained.

I'm sure there's a solution for this issue that doesn't create more maintenance work.

[ycw]

css?

[ycw]

ok, i found a way to eliminate those numbers, by auto sniffing the possible max width among tabbed panels inside the sidebar

[ycw]

done :D

[mrdoob]

Making the tabs horizontally scrollable may be a better solution.
Had to figure out the CSS for it on https://mrdoob.com/ menu some months ago...

[ycw]

done. see #28467