Feat/add external reference

[YOU54F]

supersedes #573

drops tls proxy being created and started in pact-go (added in the above pr)

includes #588

[coveralls]

coverage: 28.569% (+0.2%) from 28.36% — feat/add-external-reference into master

[rholshausen]

Can't really comment on go code, it looks like go code, but the coverage is up 0.2% so it must be good

[mefellows]

Looks good - thanks for going through all the lints as well. Good to clean house with removing some of the old functions too. I'll close off the related PRs if they haven't been done already.

[YOU54F]

Hmm looks like release failed due to commit message from merge

❯ targetBranch: master
❯ commit could not be parsed: 67d51c1d36fcb059b183f2c642a9c8217c59c1e1 Feat/add external reference (#592)
❯ error message: Error: unexpected token ' ' at 1:9, valid tokens [(, !, :]
❯ commits: 0
✔ Considering: 0 commits
✔ No commits for path: ., skipping

[mefellows]

Yeah I noticed that, it was on the TODO to look at. I think we need to do two things

1. Add a pre-merge check to ensure the commits match semantic conventions
2. Get another change in to do a release, and manually update the changelog to incorporate the items that it didn't like