Feature request: Remembering the last-used ip-address in the Android app.

[Istria1704]

Currently, when the app is closed and reopened, the IP defaults back to 192.168.1.104 and I have to manually type in the actual ESP IP each time. I thought it might be nice to either:

1. Remember the last used IP.
2. Have a dropdown list with a short IP history (in case you control multiple ESPs).
3. Have a 'default IP' setting in a separate settings page.

Maybe something for a future update. ;) Thanks a bunch for the work so far!