Remove incubation phase indications from Eclipse ESCET project page
Now that we have graduated (see #614 (closed)), we should remove all indications of incubation phase.
- See #647 (closed) for removing it from the Git repo.
- Here we focus on removing it from the project page at https://projects.eclipse.org/projects/technology.escet
- Requested the update here: eclipsefdn/helpdesk#3669 (closed)