Custom flight repo management

[TheOutdoorProgrammer]

Theres 2 problems with custom flight repos at the moment.

1. It always downloads the json every time you open chrome
2. It only supports 1 repo at a time.

I'd like to tackle this, kinda like how linux handles repo managment.

You'd have to point to a new repo via fly repo set {name} {url} (ex. fly repo set apollorion https://apollorion.com/flight_repo.json
This way every repo has a name and you can individually manage repos by name.

Then, we only fetch repo content on fly repo update and not every time a user opens the browser.

[TheOutdoorProgrammer]

close via #27