Add support for initial dry-runs

[christianhueserhzdr]

• The role will fail in initial dry-runs if package build-essential is not installed on instance, hence adding support for initial dry-runs.

[christianhueserhzdr]

I followed your line in the discussion in issue #72 and used the when keyword to simply skip 4 tasks and 2 handlers in the initial dry-runs, Tobias @tobiashuste and Norman @Normo. Would you like to have a look? Thanks.

[christianhueserhzdr]

The test sequence of the default scenario for molecule is now altered:

scenario:
  name: default
  test_sequence:
    - (dependency) # removed, unspecified
    - (cleanup) # removed, unspecified
    - destroy 
    - lint # added
    - syntax
    - create
    - prepare
    - check # added
    - converge
    - idempotence
    - check # added
    - (side_effect) # removed, unspecified
    - verify
    - (cleanup) # removed, unspecified
    - destroy

There is now an initial and a normal dry-run, linting has been added and unspecified steps have been removed.

Is this what you had in mind, Norman @Normo?