Investigate impact of GraphQL messaging instead of REST

In one of the discussions GraphQL was mentioned as an alternative for the current REST solution.
WIthin this investigation an impact analysis could be made to determine what this means for the current codebase, and what would be advantages to justify this alternative technology.

EndResult: Architectural Decision Record

Start by reviewing the current REST solution and the surrounding codebase to identify the components affected by introducing GraphQL. Compare the impact and advantages of both approaches, then document the findings, trade-offs, and recommendation in an Architectural Decision Record.

Written by the indexing model from the issue text.