[FEATURE] - Add section to documentation on battery optimisation options

[thewookiewon]

**Is your feature request related to a problem?
No

Describe the solution you'd like
I couldn't see a section in your documentation regarding battery optimisation for Android.

Just wondered what are the best settings for Samsung Galaxy S24 devices to ensure the app doesn't get auto closed / goes to sleep without using Always-On vpn.

Basically want to ensure auto tunnel will work unhindered, for samsung there are 2 areas (listed below) to use but only one can be used at any one point.

Settings > Apps > WG Tunnel > Battery > Unrestricted

OR

Settings > Device care > Battery > Backend Usage Limits > Never auto sleeping apps

Many thanks and Kind regards,

Describe alternatives you've considered
I'm currently using the first option in my above statement.

Additional context
None