Manage categories - backend

[trois-six]

Description

As we have more and more plugins in Traefik Pilot, it becomes difficult to browse the plugins page. We should add categories to sort the plugins.

Scenario

As: a user
Given: I want to discover the capabilities of Traefik plugins
When: I browse the Traefik Pilot plugins
Then: I should be able to look at only one category of plugins

Criteria of Acceptance

• fixed categories, we don't want to have categories set by developpers, as we might have a category "network" and a category "Networks" for ex
• we will have to modify piceus too to parse the categories
• we will have to explain the categories in the plugindemo README for developpers