Config.json selector / Profiles

### Your use case

#### What would you like to do?
Element-desktop should be able to be set to have no config, or to be able to be pointed at a list of config.json files

#### Why would you like to do it?
It can be helpful to pre-configure Element Desktop to login to different homeservers be default

#### How would you like to achieve it?
Add a dropdown to the login page where you can select your server?
Add a flag to execute the app with a customer json file?

### Have you considered any alternatives?

running 4/5 custom apps with different names installed

tauri wrapped hydrogen client

### Additional context

_No response_