Factorize legend for use in both amendements/debats

[njoyard]

Take care of differences between the two, both have groups on the first line but the second line is different (gov + blank + status for amendments, other participants for debates).

End-objective being, apart from factorizing code, to apply to debates the style/behavior in use in amendment's legend:

• [ ] the blank space around a legend element should be clickable as well and show the hand cursor (see https://github.com/regardscitoyens/the-law-factory/pull/165/files/6fba9375bad4ea8568d07acfdc01bc41862f1368..9f29782830b4fd66e96e5077ac7e84f47e218f3e#diff-35637e4f1f3b014927ab2623ccee5372L145 )
• [ ] the tooltips should be displayed on top instead of on left
• [ ] the tooltips should not show on legend elements for which the text is actually the same (government, auditionnés, etc.)
• [ ] clicking the background div of the legend when a legend selection is active should deactivate it the same way as when clicking on the viz background (in amendments it does)

[RouxRC]

will allow to close #115 & #119 altogether

[RouxRC]

this is already done right? although the discrepancies pointed in https://github.com/regardscitoyens/the-law-factory/pull/165#issuecomment-209130014 can let one think not completely ;)

[njoyard]

No, I've done nothing for now.

[RouxRC]

ah ok I misunderstood, this explains the legend issues in debates :) so apart from the amendment bug one i guess we can move those out to a separate issue for after merging the refacto

[boogheta]

updated the top text to reflect issues described separately in other issues

[boogheta]

And maybe rethink the way elements are organized (cf #95)