Reader Mobile App

### Description

For those who have deployed this in a local environment, it would be handy to have a reader on our phones so we can have a look at what is on our feeds on the go.

The problem I see is there are millions of readers on the app stores (Apple or Play Store) and it's difficult to find one which is a) secure and b) integrates to a self-hosted instance.

Having this available to the users means that they don't always have to browse to the feed host itself on a browser, eg. http://:8080 or https://feed.domain.com, they can just open their app and it'll automatically be in that host (or require auth if set up) and go browsing as normal.

I'd be more than happy to do testing on an Android based app myself.

The issue names no files, tests, or entry points. Start by clarifying the mobile app's scope, self-hosted instance connection, authentication, and supported platforms. Done would mean a defined app can connect to a user's host and browse feeds, with Android testing as proposed.

Written by the indexing model from the issue text.