remove 'servicehost' role

* it's unused
* our workflow covers what it's supposed to do
re-format YAML files

* this is like "one-sentence-per-line" :)
Clarify IP space
Merge pull request #17 from seankelly/ip-addr

Clarify IP space
fix secrets so they don't cause errors
Merge sa2ajj/buildbot-infra:remove-unused-role (PR #15)
Merge pull request #16 from sa2ajj/formatting

re-format YAML files
put a placeholder for the tasks
take default named config file
Merge pull request #18 from djmitche/fix-secrets

fix secrets so they don't cause errors
split named.conf

* move options to a separate file
* move zone definition to a separate file
* this way changing things when it's necessary will be easier
add the current buildbot.net zone

* as it was given in http://trac.buildbot.net/ticket/3002
simplified zone definition
first important task
make buildbot.net zone a template

* move the file
* create a variable to describ hostmaster
* create variables to describe secondary NSes
* use the variables to create actual content
ip addresses of secondaries are actually required

* main reason: restrict zone transfers to secondaries only
* another option is to resolve them at the time of installation (which
  might be or not a good idea)
generate rndc.key if it's not present

* configure named to allow operations with this key
install configuration files

* introduce a variable that points to the target directory
* update tasks to use the variable
* create necessary directories
* copy necessary files
* install buildbot.net zone
* update configuration templates to use the variable
* install configuration files using the templates
* add handler to reload configuration upon change
* enable and start named service
move traditional root hinting and rfc related zones to a separate file

* this makes the main config file a bit more manageable
update named.conf.options