VPN-6407: 15 minutes between daemon server switches

[mcleinman]

Description

Based on the data coming back from this ticket, we decided to do server switches from the mobile daemons at most once every 15 minutes. On iOS this is simply changing a variable (we had previously done one at most every 5 minutes), and on Android we had to build some new logic in.

Reference

VPN-6407

Checklist

• My code follows the style guidelines for this project
• I have not added any packages that contain high risk or unknown licenses (GPL, LGPL, MPL, etc. consult with DevOps if in question)
• I have performed a self review of my own code
• I have commented my code PARTICULARLY in hard to understand areas
• I have added thorough tests where needed