Add dynamic plugin setup/installation instruction for the janus-idp plugins

[Zaperex]

What do you want to improve?

We need detailed instructions on how to configure and dynamically install the janus-idp plugins into a backstage instance that supports dynamic plugins.

What does the current documentation state?

There are only static installation/configuration instructions for the janus-idp plugins

What would you like to be added/updated in the documentation?

Detailed instructions on how to setup and install the janus-idp plugins into a backstage instance that supports dynamic plugins. Ex: How to configure the frontend (if installed dynamically) so that it looks identical to the static installation. This usually involves having to apply the configurations in app-config.janus-idp.yaml