improve visualiszation

[jeremyszym]

Motivation

1/ A small visual improvement when the axis label is displayed here:

2/ The different graph need to be validated :

Can we confirme that the best combinasion of morphometrics ? For now we have : Colorspace (Brightness vs staturation), Aspect (Height vs widht), Greenness (Circulatity vs green index), Complexity(Perimeter vs area), Texture (Texture vs area), Solidity (bar plot)

3/Vignettes do not appears in the visualization page

[sonnyp]

@jeremyszym and @chevreuill3000 to meet and talk about a new visualization page / design