Store app websocket authentication token and port in client app's storage

Change where authentication port + auth token is stored from the holochain-service-runtime into the client apps themselves. This ensures that only approved android apps can call their happ websocket. Other android apps are not able to read that storage unless granted explicit user permission, so I believe this is good-enough security for the app ws token.

AC:
- Load authentication token + port from file in consumer app's storage area
- If not found
- Call holochain-conductor-runtime: issue_app_authentication_token
- Checks if the calling Android App Id has "user approval" for the holochain InstalledAppId
- If yes:
- generate authentication token for holochain InstalledAppId
- return authentication token
- zeroize memory
- If no:
- tauri emits a signal "request user approval"
- android-service-runtime app recives the signal, displays a notification
- user clicks "accept" on the notification
- calls holochain-conductor-runtime: approve_app
- adds Android App Id + Holochain InstalledAppId pair to "user approved apps" list
- Save authentication token + port to file in consumer app's storage area