wait for single file analysis (update)

[jstucke]

• makes intercom backend listener "responder" asynchronous (so it does not block when waiting for the result)

• converts the "single file analysis task" listener into a responder

• changes the show analysis page so that single file analyses are awaited and the page is automatically reloaded

• adds a button to the "analysis is outdated" message to quickly update it

• [ ] based on #1251 so that one should be merged first