Add Inspec provsioner support

[fatmcgav]

List of Changes Proposed

Added support for the Inspec Packer provisioner.

Testing Evidence

tox -e py27 -- tests/packerlicious/test_provisioner_inspec.py::TestInspecProvisioner::test_required_fields_missing
py27 develop-inst-noop: /Users/fatmcgav/Work/foss/packerlicious
py27 installed: atomicwrites==1.1.5,attrs==18.1.0,coverage==4.5.1,funcsigs==1.0.2,future==0.16.0,more-itertools==4.2.0,-e git+git@github.com:fatmcgav/packerlicious.git@00ecd8a7e06fb0dd259c046f968d5704e7ba8fd3#egg=packerlicious,pluggy==0.6.0,py==1.5.4,pytest==3.6.3,six==1.11.0
py27 runtests: PYTHONHASHSEED='3822679130'
py27 runtests: commands[0] | find . -type f -name '*.pyc' -delete
py27 runtests: commands[1] | find . -type d -name __pycache__ -delete
py27 runtests: commands[2] | /Users/fatmcgav/Work/foss/packerlicious/.tox/py27/bin/coverage erase
py27 runtests: commands[3] | /Users/fatmcgav/Work/foss/packerlicious/.tox/py27/bin/coverage run /Users/fatmcgav/Work/foss/packerlicious/.tox/py27/bin/pytest --basetemp=/Users/fatmcgav/Work/foss/packerlicious/.tox/py27/tmp tests/packerlicious/test_provisioner_inspec.py::TestInspecProvisioner::test_required_fields_missing
======================================================================================================================================================================== test session starts =========================================================================================================================================================================
platform darwin -- Python 2.7.15, pytest-3.6.3, py-1.5.4, pluggy-0.6.0 -- /Users/fatmcgav/Work/foss/packerlicious/.tox/py27/bin/python2.7
cachedir: .pytest_cache
rootdir: /Users/fatmcgav/Work/foss/packerlicious, inifile: setup.cfg
collected 1 item

tests/packerlicious/test_provisioner_inspec.py::TestInspecProvisioner::test_required_fields_missing PASSED                                                                                                                                                                                                                                                     [100%]

====================================================================================================================================================================== 1 passed in 0.19 seconds ======================================================================================================================================================================
py27 runtests: commands[4] | /Users/fatmcgav/Work/foss/packerlicious/.tox/py27/bin/coverage html -d /Users/fatmcgav/Work/foss/packerlicious/htmlcov/py27
______________________________________________________________________________________________________________________________________________________________________________ summary _______________________________________________________________________________________________________________________________________________________________________________
  py27: commands succeeded
  congratulations :)

[coveralls]

Coverage remained the same at 100.0% when pulling eefd8b3 on fatmcgav:add_inspec_provisioner into 793f6a3 on mayn:master.

[mayn]

thanks @fatmcgav , I'm going to sit on this for a few days while i think about the origination for community modules vs packer core.

[fatmcgav]

@mayn No worries, I appreciate that supporting non-core plugins might get a bit confusing for users.

However not sure what other options are available, as Python isn't my strong point...

[mayn]

Leaning towards putting them under a package called community Under packerlicious src. This way there is a logical separation, requiring explicit import by the user. import packerlicious.community.provisioner For example. Once imported, usage would remain the same.
Thoughts?

[fatmcgav]

Sounds like a sensible enough approach...

[mayn]

@fatmcgav, moved code to packerlicious.community.provisioner. thanks for your contribution.