webui: Switch to Asus's PPTP/OpeNVPN Server pages
webui: remove VPN switcher from pages, as we keep them as individual tabs for consistancy
webui: Implement support for running pptpd and openvpn at the same time
webui: hardcoded this page to pptpd, since we support both types simultaneously
webui: switched to Asus's OpenVPN server page; added support for second server instance; allowed to run simultaneously with PPTPD
webui: updated VPN tabs visibility based on available features