CA chart, highlight and display extra data area on chart entity selection V2

see: wiki txm-info link

When a point is selected (mouse or keyboard):

• highlight the point and its label
• show extra data informations :
  • X Y corrdinates
  • etc.

(from redmine: issue id 1683, created on 2016/02/19 by Matthieu Decorde)

added charts status::rejected type::feature + 1 deleted label

changed milestone to %TXM 0.8.2

Need to define specs: https://groupes.renater.fr/wiki/txm-info/public/specs_charts_ca

(from redmine: written on 2019/10/30 by Sebastien Jacquot)

closed

assigned to @sjacquot

added tool::ca label