Improve load time for safe-apps

[nicosampler]

When the user navigates to /apps for the first time, it takes a considerable amount of time to load it, since the app has to fetch all the apps in order to obtain the name and icon.

Related: #1303

[mmv08]

Do you have any possible solution in mind? I think this will be solved once we move apps to the backend.

[lukasschor]

From past discussions it sounded like @rmeissner is not so fond of moving the list of default Safe apps to the backend, so would not count on this necessarily.

[nicosampler]

a possible solution could be to persist in our repo the name and image for default safe-apps. it's pretty uncommon that a safe app changes its name or icon, so it could work.