Support for controls clause, more options available out of 'extra_options'

[LAripping]

Mostly additions, PR does not break anything. In detail:

1.Support for controls clause. Conf. template providing options regarding the rndc channel the user might use. (Also requested in #63) 2.Many common options can be specified without the use of extra-options. Namely: * allow-new-zones (yes | no) * allow-notify (IP adr. list) * notify (yes | no | explicit) * auth-nxdomain (yes | no) * request-ixfr (yes | no) 3. DNSsec options are now not mandatory, so their values are not printed in the conf file if they are not specified. 4. Location of the key-file is now parametric. Again, template adds it in the configuration only if the path is explicitly specified.