Otherwise the enable during image create will throw a few error messages

Do not use 'red' as text color on input fields with errors as the
backgronud color is already red, rendering the value unreadable.

Display the correct hostname on the final page of configmode.
Previously, this page used to simply call luci.sys.hostname() which
would return the current hostname. However, when the configmode changes
the hostname luci.sys.hostname() will not reflect this. This patch
fetches the hostname directly from the UCI system config.

This adds a variable called 'hostname' which may be used in site.conf at
config_mode.msg_reboot and .msg_pubkey.

This reverts commit f5c532a3a923053ab229952bde31da0b0284d8ab.

The reboot page should be delayed a little to give the browser time for
fetching assets (like the stylesheet). This adds a two second delay.
Unfortunately, I couldn't think of a sane way to do this within a luci
controller.

This patch forks the process. The parent will continue rendering the
page for the browser while the child will sleep and then reboot the
device. For this to work reliable the child needs to close stdout before
sleeping so the webserver closes the connection to the browser. This,
again, required a hack as lua does not allow closing std filehandles,
when prevented using luci.reboot() which was calling os.execute() and
that function will not work with stdout closed.

gluon-luci-admin: various changes

add new luci-theme

Don't refresh the reboot page after rebooting the node. It's not going
back to configmode anyway so it'll never reload without user
intervention.

This completely replaces the text on the overview page. Consider this a
placeholder until someone writes a better suited version :)

Hide the "logout" button when in configmode.

Replaces double-spaces with tabs to match surrounding code.

For security reasons we'd like to disable all HTTP config interfaces
when the node is operating normally. This patch disables gluon-luci-admin
when configmode is not enabled.

Those headings do not convey much information make the wizard less
compact. The help texts will be rewritten to guide the user instead.

Replace the inline stylesheet for the public key box on the reboot page
with a CSS class so it can be styled using the theme.

This makes gluon-config-mode and gluon-luci-admin depend on
gluon-luci-theme instead of luci-theme-openwrt.