Speed up loading of plugin icons (perhaps add caching?) in the Plugins UI

[anna-geller]

Describe the issue

See https://share.descript.com/view/Kqgjrr0M1o2

When you do a kestra demo, the icons that don't load at first give the impression that something isn't working.

Environment

• Kestra Version:
• Operating System (OS/Docker/Kubernetes):
• Java Version (if you don't run kestra in Docker):

[MilosPaunovic]

I did a bit of digging around this one and it turns out that the biggest issue which slows everything down is the plugins/icons/groups endpoint, which takes approximately 2 seconds to complete every time.

Could we check with someone on the BE team how is this implemented and could we improve the response time?