Add build option to remove all internal RC4 uses

Add build option to remove all internal RC4 uses

The new CONFIG_NO_RC4=y build option can be used to remove all internal
hostapd and wpa_supplicant uses of RC4. It should be noted that external
uses (e.g., within a TLS library) do not get disabled when doing this.

This removes capability of supporting WPA/TKIP, dynamic WEP keys with
IEEE 802.1X, WEP shared key authentication, and MSCHAPv2 password
changes.

Signed-off-by: Jouni Malinen <j@w1.fi>