doc: images organisation

Proposal

In static/img one directory per page or component.

How do other docusaurus projects do it? Are there any good practices in the docusaurus doc? If not, follow the naming convention of the components or pages.

For example

• the page src/pages/communaute.mdx has its images in static/img/pages/communaute
• the component src/components/HomepageFeatures.js with its images in static/img/components/HomepageFeatures
• the docs/Gestions des plans/etang_users.md to its images in static/img/docs/Gestions_des_plans/etang_users

To do

• propose to @cchaudier an organisation
• Document organisation
• Refactor code to follow this organisation