Add margins to separate svg charts
Add borders around each chart
Remover borders around each chart

Borders are distracting and push viewers to consider each chart
separately, losing the comparison between charts.

This reverts commit 198b598a85664e03cfd2b88e23d8dc0ca6cf036f.
Keep charts flush left

The margins are now only right and below.
Extract function getWorkingGroupLayout()

This is a first step before sharing the same code for this
common layout in various charts.
Add parameter to customize group names in getWorkingGroupLayout()
Reuse getWorkingGroupLayout() in separate charts for each AR
Add identity() function to code-utils.js
Replace groupNames hash parameter with getGroupName() function

This makes the definition less redundant and grants more flexibility.