Set up graphql in Static Site Editor

What does this MR do?

Sets up a new instance of ApolloClient for the Static Site Editor and injects a VueApollo provider to the Static Site Editor app. It also creates type definitions for initial local state data. This MR is part of the effort to adopt GraphQL in the Static Site Editor. You can see more details of the frontend efforts in #216186 (closed).

To understand the whole effort, see &3183 (closed).

Next Merge Request: !30882 (merged)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content