Adding icons to pages and topics

**Is your feature request related to a problem? Please describe.**

Our client would like to add icons to the pages and topics to visually differentiate different types of pages and topics on the "Help" pages. **Describe the solution you'd like**

Add possibility to define icons for pages and topics. **Describe alternatives you've considered**

The whole CMS should be thought out from ground up, as the current CMS features of Decidim are very limited. This could be part of thinking how to manage content and navigational structures within the system in the bigger picture (e.g. navigating Metadecidim to find the feature proposal form takes 4 clicks if you're already signed in, is this good usability?). **Additional context** Add any other context or screenshots about the feature request here.

Related ideas:

• Allow defining static page content using the content blocks
• Allow adding multiple same type of content blocks on page
• Possibility to configure the top level navigation
• Possibility to configure the participatory space navigation

**Does this issue could impact on users private data?*

Nope.