render diameter when a feature is selected

[k-yle]

If a node has a tag like diameter or radius, iD will now render a circle when you select the node.

• As per the wiki, spaces are allowed between the number and the unit.
• These tags are supported: diameter, diameter_crown, hole:diameter, radius, crown_radius, and seamark:anchor_berth:radius.
• Many different units of measurement are supported, including a combination of feet and inches
• The default unit is m for all tags except diameter, where the default unit is mm and seamark:anchor_berth:radius where the unit is defined by a separate tag (seamark:anchor_berth:units)

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does not exactly fix #9189, but solves the problem with an alternative solution

[tordans]

I really like this idea. We are using diameter on trees a lot in Neukölln to render a more realistic Map like https://strassenraumkarte.osm-berlin.org/?map=micromap#19/52.47378/13.43892 so that will help at lot to get a feel for this value.

[tyrasd]

Regarding the concrete styling: I think the red-ish color is a little bit distracting in this context. It reminiscent of the color iD uses for buildings, or could be interpreted as an error even.

What about going with a neutral styling similar to the viewport cones?

g.point .radius,
g.vertex .radius {
    fill: #333;
    fill-opacity: 0.6;
    stroke: #fff;
    stroke-width: 0.5px;
    stroke-opacity: 0.75;
}
.fill-wireframe .radius {
    fill: none;
}

[k-yle]

styling also changed per suggestions above:

[matkoniecz]

@k-yle

This branch has conflicts that must be resolved

[k-yle]

@matkoniecz almost all my PRs will have that label, because editing the CHANGELOG file will create conflicts if a different PR is merged first