Add permissions for PWAs

[danielmota]

Add permissions to not depend of Flatseal.

[flathubbot]

Started test build 183169

[flathubbot]

Build 183169 successful
To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/166376/com.google.Chrome.flatpakref

[Bohne13]

It's the same like #298 and #188

and it should be like the #298 with the ':create' at the end.
This ensures that the location is created if not existened.

# To allow installing Progressive Web Apps (PWAs)
 - --filesystem=~/.local/share/applications:create
 - --filesystem=~/.local/share/icons:create

I would close and combine these MR's but as far as I know, it's only possible by the owner of this repo.