Pagination headers

[kminehart]

Related issue

#1047

#1357

Proposed changes

To improve user experience, pagination needed to be improved without making backwards-incompatible changes to the JSON payload.

Now, for API requests where limit and offset are accepted, a Link header containing URLs for the "first", "next", "previous", and "last" pages is also sent. If any of those pages are not applicable, then the URL is not included.

Updated the Makefile to handle generating the migrations better. On a newer Go environment I wasn't able to create the migrations; go-bindata/go-bindata wasn't finding any of the SQL files. Instead of only pointing to the directory, I added ./... to recursively search for files to convert.

Checklist

• I have read the contributing guidelines
• I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security
  vulnerability, I confirm that I got green light (please contact hi@ory.sh) from the maintainers to push the changes.
• I signed the Developer's Certificate of Origin
  by signing my commit(s). You can amend your signature to the most recent commit by using git commit --amend -s. If you
  amend the commit, you might need to force push using git push --force HEAD:<branch>. Please be very careful when using
  force push.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)
• I have documented my changes in the developer guide (if appropriate)

Further comments

I added tests for the manager functionality that was added, however I was unable to find a way to add headers for swagger build (in the comments in handler.go). I was hoping that the Link header generated / documented in the SDK, but I couldn't find a way to do it in go-swagger's documentation.

Any advice, @aeneasr?

[aeneasr]

Regarding Headers, I was only able to find this comment: go-swagger/go-swagger#70 (comment)

Maybe, for now, we just add this in the description portion?

[aeneasr]

Awesome!