Feature: Client Interface Selector - #2077

This PR attempts to address Feature Request #2058

• Adds Interface Selector to Wifi Client page
  • Only shows wireless interfaces and uap*
• Reworked logic of how AP and Client interfaces are determined and/or defaulted
• Added ability to override client interface when POST submitted
• Added Service Interface labels on Hotspot & DHCP interface selectors to match new one
• Requires adding wpa_cli disable_network to sudoers

ToDo

• Persist preference in system config on the file system