[FEATURE]: Built-in color picker/wheel

[Gazook89]

Since the tool is primarily for spiffy-ing up brews, it seems it should include a color wheel/picker as part of the interface. Personally I already have a color wheel browser extension, but I imagine that many users do not and may not have a great understanding of CSS color values.

[ericscheid]

As a custom menu item on the Style pane? Or maybe like this, where ctrl-k invokes the picker?

[G-Ambatte]

[...] Or maybe like this, where ctrl-k invokes the picker?

I like that one; if I'm reading the documentation correctly, we could set it up with a custom palette for colours that are already commonly used in HB.

[calculuschild]

This may be folded into #1870