feat: allow percentage-based inputs in color picker

[matmen]

Closes #1368

[matmen]

Also, I'm not sure if there should be a setting (either server-wide or saved in the browser) to set a default value range. @thijstriemstra Would you mainly be using the 0..1 range and would remembering the last selection be useful in your case?

[thijstriemstra]

Would you mainly be using the 0..1 range and would remembering the last selection be useful in your case?

Not sure what you mean..

I would refer to the klipper docs on [neopixel](and [led]): https://www.klipper3d.org/Config_Reference.html#neopixel

#initial_RED: 0.0
#initial_GREEN: 0.0
#initial_BLUE: 0.0
#initial_WHITE: 0.0
#   Sets the initial LED color. Each value should be between 0.0 and
#   1.0. The default for each color is 0.

As well as: https://www.klipper3d.org/G-Codes.html#led

Each color <value> must be between 0.0 and 1.0. The WHITE option is only valid on RGBW LEDs. 

[matmen]

@thijstriemstra I'm just asking if you want an option to remember the last choice (either 0..255 or 0..1) so you don't have to switch to 0..1 every time you open the color picker (if you primarily use the 0..1 option) :D

[thijstriemstra]

you don't have to switch to 0..1 every time

oh, yes, good idea. Just wanted to point out some people need 4 input fields (RGBW leds).