fix(plugin.legend): refactor legend plugin to avoid duplicate logic and fix multiple issues

- chartjs#12067 keep all the hitboxes in the same column with the same width so we can align the label text properly
- chartjs#11850 make sure the title can fit
- chartjs#12066 respect the horizontal paddings of the title
- chartjs#11824 always measure item height to account for multiline legend items
- chartjs#11805 respect max width and height in both horizontal and vertical

Close chartjs#12067, chartjs#11850, chartjs#12066, chartjs#11824, chartjs#11805

Author: adrianbrs