Add a centralized Swagger-UI for all OpenAPI specs

[Tristan-WorkGH]

Add a swagger-ui on http://localhost:9080/swagger/ that can show the specs of any server.

Why? because we haven't to remember what is the port of each server.

[!NOTE] The servers have CORS activated with rules that forbid another domain. ~So a plugin is needed to force the navigator to ignore CORS rules, like:~

• ~https://addons.mozilla.org/firefox/addon/cors-unblock/~
• ~https://chromewebstore.google.com/detail/cors-unblock/lfhmikememgdcahcdlaciloancbhjino~
• ~https://microsoftedge.microsoft.com/addons/detail/hkjklmhkbkdhlgnnfbbcihcajofmjgbh~

An overlay in nginx is done to relay from the same domain the specs that are on different servers (ie domains for navigators). That induce a rewrite of urls through a swagger plugin to be transparent to the user.

[!NOTE] A dark theme has been added for the ease of eyes 😄