[web] Implement Events for "Space metadata"

[kulmann]

Description

User Stories

• As a user, I want to see in real time in my client when a space gets renamed or the description (in web ui: Subtitle) changes so that I don't get confused when someone is talking to me about a space where I don't recognise the space name.

• As a user, I want to see in real time in my client when the space special items (image and readme) change so that I always have the space look and feel and info that my coworkers have as well.

Value

Transparency, feeling of live collaboration

Acceptance Criteria

• Update the space name or subtitle in the ui when the space fields name or description get changed remotely and published via SSE
• Update the space image and description in the ui when the space special items image and readme get changed remotely and published via SSE

Definition of ready

• [ ] Everybody needs to understand the value written in the user story
• [ ] Acceptance criteria have to be defined
• [ ] All dependencies of the user story need to be identified
• [ ] Feature should be seen from an end user perspective
• [ ] Story has to be estimated
• [ ] Story points need to be less than 20

Definition of done

• Functional requirements
  • [ ] Functionality described in the user story works
  • [ ] Acceptance criteria are fulfilled
• Quality
  • [ ] Code review happened
  • [ ] CI is green (that includes new and existing automated tests)
  • [ ] Critical code received unit tests by the developer
• Non-functional requirements
  • [ ] No sonar cloud issues