How to load components dynamically in a sidebar

### Issue type

**I'm submitting a ...** (check one with "x")

* [ ] bug report
* [x] feature request
* [ ] question about the decisions made in the repository

### Issue description

**Current behavior:**
In the current ngx-admin portal it is very easy to load items in the central part of the application (using the main router-outlet). However, I find it difficult for example to load a right sidebar with content of choice (like message center, email center, triggered from icons from the header). I have tried many things, but all fail.

**Expected behavior:**
How to adjust the ngx-admin portal demo to dynamically load routes in a right sidebar, from dynamically loaded modules.

Thanks for the assistance!