docs: product roadmap and zitadel versions (#9838)

# Which Problems Are Solved

The current public roadmap can be hard to understand for customers and
it doesn't show the timelines for the different versions. which results
in a lot of requests.
It only outlines what is already fixed on the timeline, but doesn't give
any possibilities to outline future topics / features, which not yet
have a timeline

# How the Problems Are Solved

A new roadmap page is added
- Outline for each version when it will have which state
- Outline different zitadel versions with its features, deprecations,
breaking changes, etc.
- Show future topics, which are not yet on the roadmap

docs/docs/guides/manage/customize/branding.md

@@ -46,7 +46,7 @@ If you like to trigger your settings for your applications you have different po
 Send a [reserved scope](/apis/openidoauth/scopes) with your [authorization request](../../integrate/login/oidc/login-users#auth-request) to trigger your organization.
 The primary domain scope will restrict the login to your organization, so only users of your own organization will be able to login.
 
-You can use our [OpenID Authentication Request Playground](/oidc-playground) to learn more about how to trigger an [organization's policies and branding](/oidc-playground#organization-policies-and-branding).
+You can use our [OpenID Authentication Request Playground](https://zitadel.com/playgrounds/oidc) to learn more about how to trigger an [organization's policies and branding](https://zitadel.com/playgrounds/oidc#organization-policies-and-branding).
 
 ### 2. Setting on your Project