display multiple source files on UI

for a given entity in the ui, now multiple sources might contribute to the record. This is to

• decide how to deal with this at the level of the UI
• implement the solution

Note: this issue is created from remains of [ui "milestone"](https://codebase.helmholtz.cloud/hmc/hmc-public/unhide/development/strategyandplanning/-/issues/9) in order to preserve it as backlog