Alignment improvements in the Layer control

[Malvoz]

• a056aa0: re-use CSS to avoid duplicating user-select styles
• ed8687d: align the checkbox with other controls (also removes unnecessary width and the need for an !important statement)
  
  Before:
  
  After:
  
• b4f5afe: remove text-align on the layer name (because it 1: doesn't appear to be needed, and 2: doesn't look good if the map is set to RTL direction but the layer name is in an LTR script)
  
  Before:
  
  After:
  
  (i.e. now looks good independently of the direction of the map and/or the script used in the layer name, tested using sample arabic text)
• c95d4e3: removes the indentation/margin for better alignment and improves alignment between labels and radio inputs (also fixes an RTL issue)
  
  Before:
  
  After:
  
• b6f59f0: add padding to the layer name (see screenshot below)

[ahmadayubi]

I like the alignment changes as it makes it more consistent but I guess it's up to preference.

[Malvoz]

c95d4e3: Removes the indentation/margin for better alignment

The original indentation was intentional, but I don't remember if not indenting the opacity slider was intentional or not. I think the logical thing is to either indent all input controls or don't indent any. While I think indenting looks better when you expand all details elements, it kind of looks strange with only having the opacity slider visible:

as opposed to:

It's not a big deal I guess, but if you prefer one thing over the other let me know. 🙂

[prushforth]

I prefer the indented version. Thanks!

[Malvoz]

@prushforth I've indented all the settings (including opacity slider) in 15d3ed4:

Feel free to merge, or let me know if there's anything else. 👍

[prushforth]

Looks good!

[Malvoz]

While I'm at it, pushed b6f59f0 to give the layer item name some padding in the block direction (top/bottom in this writing mode):

Before:

After:

(the effect of the padding is only visible if the layer name is long enough / layer name's container is small enough that the layer name wraps and exceeds the height of the container)