Use separate configs for 802.11g & 802.11a bands

This changes the metrics variables that invove scores to arrays.  At the
momemnt, there are two bands implemented, 802_11a and 802_11g.
Internally, they are chosen based on the frequency of the channel being
used.  Anything < 2500 MHz is 802_11g, and everything else is 802_11a.
Dawn will issue a warning if it finds a frequency greater or equal to
5925 MHz.  The upper limit of the 802.11a band, and the start of the
next band vary by country, so this will have to be reviewed.

The UCI configuration changes.  Instead of a single metric config, there
will be a global metric config, and one for each band.  The
non-band-specific configuration will only work in the global config.
Any per-band configuration present at the global config will be applied
to all bands.  Any configuration present at the specific band will
override any global values.

The following configuration options are split into bands:
 - ap_weight
 - ht_support
 - vht_support
 - no_ht_support
 - no_vht_support
 - rssi
 - rssi_val
 - low_rssi
 - low_rssi_val
 - freq
 - chan_util
 - max_chan_util
 - chan_util_val
 - max_chan_util_val

Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>

src/test/simple_kick.script

@@ -1,5 +1,5 @@
 dawn default
-dawn min_kick_count=2
+dawn min_number_to_kick=2
 ap bssid=11:22:33:44:55:66 neighbors=112233445566
 ap bssid=22:33:44:55:66:77 neighbors=223344556677
 client bssid=11:22:33:44:55:66 client=ff:ee:dd:cc:bb:aa