feat(bar): bar label and tooltip always visible

[oldru27]

Commit 1f1dc8c

• Make sure the bar label is centered on the visible part of the bar, even when the bar overflows on the left or on the right.
• The bar label is wrapped into a container whom position is calculated based on the barContainer position and bar position (xStart, xEnd)

Commit 0c5a50e

• Make sure the tooltip is always visible on the left part of the bar, even when the chart is not positioned all the way to the left
• The tooltip left position take into account the left position of the Chart

Closes #127