[Feature]: Make it possible to open a github repo/branch in UI via URL arguments

[neubig]

What problem or use case are you trying to solve?
Describe the UX of the solution you'd like

It would be really cool if we could create a link with every pull request that said "Open in OpenHands" that would link to a hosted version of OpenHands already initialized with the target repo and branch.
Then if a pull request needs some additional work, then we could open it up very easily in OpenHands, and then ask it to make any changes, and push them back.

Do you have thoughts on the technical implementation?

In order to do this, we'd need to accept the repo name and branch name as url arguments. If these are passed in, we could skip the initial splash screen and jump directly to the main app with the repo initialized.