WIP: Initial conversion for packer 1.7

[frank-m]

Hi,

I did an initial conversion for packer 1.7.

I followed https://www.packer.io/guides/1.7-plugin-upgrade and got it building.

Updated the tests as well, but still need to verify them

Oh and after merging, the repo needs to renamed to packer-plugin-dsc, else it won't work with the new packer init installation.

[mefellows]

This is great, thanks. I'll take a look this weekend

[fbinotto]

Did you have a chance to check this? It would be great to use it with packer 1.7+

[mefellows]

Apologies, I did forget about this.

What's needed to get this in? I haven't used Packer for a while so I am a little out of touch with the latest and greatest.

[fbinotto]

@frank-m any guidance here?

[levindzmitry]

I assume this repository needs to be renamed to something without "packer-" prefix because such prefix is NOT allowed in >1.7 packer version. Then this pull request needs to be approved.

[mefellows]

I no longer have any time to commit to this project. I think somebody should fork it, and I will then update the readme to note the project has been superseded and where to go.