Replace app ID in notifications with app URL instead

[jdaviescoates]

Getting notifications like:

The redis-80da3f0e-1af9-4aad-b0eb-6adbb322d493 service ran out of memory

Is not very useful, as you then have to track down which app that is.

Being able to search My Apps by app ID would help, but it'd be much nicer if notifications just gave the app URL instead of the app ID (much like the similar recent change to backup names)