802.11ac - specific config requirements for hostapd

Hello,

Please consider to add to WUI (cgi-bin/wlanap.cgi) a field where specific 802.11ac settings can be added. Ex: vht_oper_chwidth=1 vht_oper_centr_freq_seg0_idx=42

Others specific settings might be needed - as listed in the hostapd configuration file https://w1.fi/cgit/hostap/plain/hostapd/hostapd.conf

Currently these settings added to /etc/hostapd.conf don't survire when WUI is used - settings need to be added back afer WUI is used and hostapd restarted.

Thank you for considering this improvement, Horace