[Enhancement]: Cleanup color management

[Caellian]

@bi4k8 mentioned this in #1504 and I agree:

I think we need to decide once and for all how to handle alpha in Conky: is it separate from colors, or included with them? We conflate ends and means in the current configuration scheme: own_window_transparent overrides own_window_argb_value, but should really be equivalent to own_window_argb_value = 0, except that it actually triggers a different implementation that can work in more X11 configurations. Meanwhile, color parsing does support reading alpha values, except for places where the parsed alpha is overridden by xftalpha or own_window_argb_value.

Originally posted by @bi4k8 in #1504 (comment)

This is very confusing to deal with by users. As a user I'd expect a single window_background = "color" property that also accepts alpha, and then for conky to deal with all the implementation details.

There are however 3 different config options for this "1 concept":

• own_window_argb_value
• own_window_colour
• own_window_transparent

And additionally own_window_argb_visual that, when I forget about implementation details of X11, doesn't tell me much.

I suggest the first three to be replaced with simply window_background_colo(u)r, and for the own_window_argb_visual to be renamed to enable_x11_true_transparency because that communicates so much more details at a first glance:

• I know there's "fake" transparency
• I know it's only X11
  • because Wayland makes it hard to do the other (worse) thing
• I know it has (almost) nothing to do with actual "rgb" color value.

[Caellian]

When implemented, this can't break old configs, so old values should be propagated to new ones.