Updated sip.conf management

+ Moved sip.conf from `file` to `concat` resource
+ Broke up sip.conf into three sections
+ Added ::asterisk::config::device defined type
  - Allow multiple sip devices to be created
Device and template cleanups
Use `if !()` instead of `unless` for Puppet 2.7

`device.pp` updated to use compatible expression syntax over newer
keyword `unless`.

Ref: https://docs.puppetlabs.com/puppet/2.7/reference/lang_expressions.html
Merge pull request #12 from runswithd6s/sipconf

Updated sip.conf management