Update Signals Docs

[timdeschryver]

Information

Update signal docs on the new website located at https://github.com/ngrx/platform/tree/main/projects/www/src/app/pages/guide/signals

This can be done after the following PRs are merged:

• docs(signals): update FAQ page according to latest changes #4791
• docs(signals): apply new naming convention from Angular styleguide #4790
• docs(signals): move withFeature section after custom features with input; improve description #4789
• docs(signals): add Events page #4788

[timdeschryver]

Closing this, it will be easier to just copy the content on the release of the new docs.