Add some DAP endpoints to spec file

[telday]

What does this PR do?

Adds some of the DAP endpoints to the OpenAPI spec and adds integration tests for the new endpoints as well as infrastructure to run them.

In the name of minimizing the amount of time spent on this one PR I have excluded two things which issues should be opened to add later:

• The configuration/{account}/seed/follower endpoint
• Running the API contract tests against DAP

Before the Jenkins CI tests will run properly this PR on dap-intro needs to be merged in.

Follow up issues:

• 166 - update integration tests for enterprise

• 167 - add enterprise endpoint info to wiki page

What ticket does this PR close?

Resolves #144

Checklists

Change log

• [x] The CHANGELOG has been updated, or
• [ ] This PR does not include user-facing changes and doesn't require a CHANGELOG update

Test coverage

• [x] This PR includes new unit and integration tests to go with the code changes, or
• [ ] The changes in this PR do not require tests

Documentation

• [x] Docs (e.g. READMEs) were updated in this PR, and/or there is a follow-on issue to update docs, or
• [ ] This PR does not require updating any documentation

[telday]

@izgeri A follow up issue should definitely be filed for updating the Wiki page. I think the easiest way to track the Enterprise version is just to add another version file named ENTERPRISE_VERSION and change the SERVER_VERSION file to OSS_VERSION. I may be wrong but I believe the three other endpoints are added by evoke, so should we be adding the evoke version anywhere? Or just the Conjur Enterprise version?

167 opened to follow up on updating the spec wiki page.

[telday]

@izgeri #160 is merged in. Just need an approve on this after the rebase