Add performance platform/data-in adapter

This supports submitting service feedback aggregate data.
Merge remote-tracking branch 'origin/add-pp-data-in-adapter'
bump version to 8.3.0
PP data-in for service feedback: fix url construction

To submit service feedback to the PP, slugs need to be adjusted
to replace dashes with underscores (<sigh>)
Merge pull request #117 from alphagov/fix-pp-data-in-api-url-construction

PP data-in for service feedback: fix url construction
Bump version to 8.3.1
PP data-in for service feedback: update url construction
Merge pull request #119 from alphagov/update-pp-data-in-api-url

PP data-in for service feedback: update url construction

* Currently performance platform provides two methods for writing to a data-set ('bucket'):
  - Writing directly into the collection name (which has underscores, because it's mongo)
  - Resolving which data-set is written to by providing `/data-group/data-type` e.g. 'apply-for-a-thing/customer-satisfaction'

* The second method is preferable in the case of customer satisfaction as it more clearly resolves to slugs from mainstream.
Bump version to 8.3.2
Add feedback_url to Support.
Merge pull request #120 from alphagov/add_support_feedback_url

Add get_feedback_url to Support.
Bump version to 8.4.0
Rename industry sectors to specialist sectors
Merge pull request #121 from alphagov/rename-industry-sectors-to-specialist-sectors

Rename industry sectors to specialist sectors

https://github.com/alphagov/panopticon/pull/126
Bump version to 8.4.1
Remove panopticon#curated_lists accessor.

The corresponding endpoint in panopticon was removed in
https://github.com/alphagov/panopticon/commit/7e6388fb4698be5178ce27708cf86895ef67e8ee
a year ago.
Remove test of removed endpoint
Add a script for Jenkins branch builds.
Merge pull request #122 from alphagov/remove_call_to_removed_curated_lists_endpoint

Remove panopticon#curated_lists accessor.
Prevent branch builds publishing the gem.

To publish the gem after a successful build, we now need to set the
`PUBLISH_GEM` environment variable.

This changes the conventional behaviour of `jenkins.sh`, but as @alext
pointed out, it's better to break convention and fail safely than to
keep with convention and fail dangerously.

Branch builds technically shouldn't end up publishing anyway, so long as
everyone follows the rule of not bumping the gem version on a branch
build, but it's better not to take the risk.