Use UCI config_get_bool enabled instead of config_get enabled

[stokito]

Maintainer: @myszsoda @csonsino @1715173329 @dangowrt @ysc3839 @feckert @blocktrron
Run tested: VirtualBox, but tested only the one

Description:
When reading an enabled option from the UCI config we should use the config_get_bool function instead of just config_get. The reason is because a user may not remember and put not just the 1 but on, yes, true or enabled.

To avoid potential problems and to make all the code looking similar I changed all places from the config_get enabled to config_get_bool enabled. Other boolean options may also need for the change. The only place that I didn't changed in tor-hs package because this fixed in #21642

Another potential problem is that some UCI configs use the option name enable instead of more widelly used enabled.
A user may type enabled and be wondered why it doesn't have any effect.
We have seven places which are using the enable:

net/atftp/files/atftpd.init
net/natmap/files/natmap.init
net/nut/files/nut-cgi.init
net/openvpn/files/openvpn.init
net/sslh/files/sslh.init
net/usbip/files/usbipd.init
utils/collectd/files/collectd.init

We may add an additonal call to config_get_bool enabled and deprecate the old option enable but I believe this is minor thing. We just have to check for this error during a code review to not allow for a new code that uses the enable.

[1715173329]

LGTM, thanks!

[neheb]

hmm? commit is missing description.

[stokito]

@neheb sorry, I fixed ad added the comment:

The config_get_bool function parses not just the 1 but on/yes, true/false or enabled/disabled.