Handle errors in Browser.svelte

[sebastinez]

Hey @rudolfs I brainstormed a bit on a way to handle eventual errors in the Browser component. I agree that this solution is not the cleanest, but I feel like it's very explicit and self explaining, with these new catch clauses. wdyt?

I feel like we should have some component error state, that when somewhere trying to get a blob, readme or tree, an error should bubble up and throw the entire browser component into an error state.. Since currently we are moving a lot to the console, and the user eventually doesn't know whats going on.. But I have to think a bit longer on this one