Local network setting for use without relying on NAT hairpinning or local DNS

### Actual behaviour

Can't connect to Nextcloud instance if it's on local network.

### Expected behaviour

It'd be nice (and convenient) to be able to choose a local network, just like you can do with Transdroid (Settings > Servers > [Your server] > Advanced settings > Local Network and Local IP or host). My server runs inside my home network and it is very annoying to have to either change the settings when I get home or to have to access my Nextcloud instance using mobile data. I hope this makes sense.

### Steps to reproduce
1. go to local network
2. open app
3. doesn't work

### Environment data
Android version: irrelevant

Device model: irrelevant

Stock or customized system: irrelevant

Nextcloud app version: 1.4.1
Nextcloud server version: 11.??