Use open directory portal

[danirabbit]

We can't read other app's appinfo in the sandbox, so remove the open in submenu. There is a portal for showing a file in Files, so use that portal

[zeebok]

I think my only real reservation is that this creates a tight dependency on Files being on the user's system. Is this something we are alright with?

[danirabbit]

@zeebok Since it uses the portal it launches whatever file browser you have installed :)

[danirabbit]

Yeah this project is wild in that it has so much abstraction and none of it is DRY lol