"Automatic" inner color

Inner color defined in statuses or templates is defined according to functional color, to highlight the inner. In the case of a dark functional color, the inner color is set to "white".

However in the case of "plain = false" or a gauge, the background is white and the border of the functional color => invisible inner.

→ Force the inner color to "black"

In Map Component:

• Functional color and additional ones proposed by @mccart77 will be available through default status and templates, defined for markers (see https://github.com/Orange-OpenSource/IOT-Map-Component#presentation)
• But we also will leave the developer free to use another color

At the same time, we would like to simplify the use of the component by setting the color of label/icon to white vs. black according to the background color of the marker.

Can be done according to the following algorithm (which is aligned with @mccart77 specifications for functional markers color):

• Background Luminance = .3R+.6V+.1B
• If Luminance >= 128 set the icon / label in black
• If Luminance < 128 set the icon / label in white

Start in the Map Component's marker color handling and trace how statuses and templates set functional and inner colors, including plain=false and gauges. Implement the stated luminance threshold so labels and icons use black or white appropriately, and verify that the inner color remains visible in the described cases.