[chore] A round of Kobo specific script cleanup (#3876)

* Flag those scripts as executable in git

Somewhat irrelevant because we'll end up living on a FAT32 drive, but,
still.

* Cleanup Kobo startup script

Support KFMon >= 0.9.5

Don't siphon PRODUCT from nickel, it's exported by rcS, so fmon/KFMon
already inherit it.
Siphon NICKEL_HOME, on the off-chance nickel fails to figure that one
out for itself on restart.
Siphon LANG (This may be a terrible idea, rcS sets LANG to en_US.UTF-8,
while we set LC_ALL to en_US.UTF-8, but I don't know if nickel itself
ever updates LANG, since I have mine set to en_US also ;)).
My secret hope if that everything's working as it should and this ensures
we default to Nickel's locale on fresh installs?

Remove the extra sync on startup, both @Baskerville's fmon and KFMon are
smart enough not to do anything overly stupid, and recent FW versions
have a slightly more resilient DB anyway (rollback journal -> WAL).
This effectively shaves over a second off our startup time.

* Slimmed down the nickel restart script.

Based on current rcS
Scrapped a bucketload of irrelevant & legacy crap, since we're never
bootstrapping nickel, only restarting it.

* Update Kobo install instrcutions.

Point to KSM09, @Baskerville's fmon, and KFMon.
Deprecate legacy fmon, and as such, stop shipping a useless KoboRoot
tarball.

platform/kobo/enable-wifi.sh

@@ -5,11 +5,14 @@
 lsmod | grep -q sdio_wifi_pwr || insmod "/drivers/${PLATFORM}/wifi/sdio_wifi_pwr.ko"
 # WIFI_MODULE_PATH = /drivers/$PLATFORM/wifi/$WIFI_MODULE.ko
 lsmod | grep -q "${WIFI_MODULE}" || insmod "${WIFI_MODULE_PATH}"
-sleep 1
+
+while [ ! -e /sys/class/net/eth0 ]; do
+    usleep 200000
+done
 
 ifconfig eth0 up
-wlarm_le -i eth0 up
+[ "$WIFI_MODULE" != "8189fs" ] && wlarm_le -i eth0 up
 
 pidof wpa_supplicant >/dev/null \
     || env -u LD_LIBRARY_PATH \
-        wpa_supplicant -D wext -s -ieth0 -O /var/run/wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant.conf -B
+        wpa_supplicant -D wext -s -i eth0 -O /var/run/wpa_supplicant -c /etc/wpa_supplicant/wpa_supplicant.conf -B