Add ability to include custom tags in InSpec

[rlakey]

Currently we cannot add additional metadata to the InSpec code that is generated.

Proposing either adding an option to include component "Addtional Questions" as additional tags or add a new option to specify new key,value custom tag data to add to controls in a component.

Currently we have these tags that are auto generated:

tag severity: 'low'
tag gtitle: 'SRG-APP-000141-AS-000095'
tag gid: nil
tag rid: nil
tag stig_id: 'VABC-50-000142'
tag cci: ['CCI-000381']
tag nist: ['CM-7 a']

Custom tags would be the same so if we had an additional question of "Color" with a value of "Blue" we could check a box to indicate it should be added as a tag.

tag color: 'Blue'

[aaronlippold]

My original thought for this was that we had both a 'tags' and 'inputs' table for each Vulcan project so that the project would know what tags and inputs had been used in the controls already and we could avoid duplication or 'like inputs/tags' from being introduced.

Much like in github were the system knows 'labels' that exist and suggest you reuse rather then recreate.

Aligning that controls use of that tag or input may be something we add the the 'constructor' as an optional object we can pass in at runtime / create time.