backend: migrate go-bindata to embed

[tylerauerbeck]

Migrate from go-bindata to embed

This migrates the usage of go-bindata to use the native functionality provided by embed. This will allow us to clean up an unmaintained dependency and ultimately appears to make the functionality provided a bit easier to understand.

How to use

With a running empty database

docker run --name nebraska -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=nebraska -e POSTGRES_DB=nebraska -p 5432:5432 -d postgres

• Run make run-backend
• Confirm database tables appear as expected

Testing done

This was tested manually as mentioned above. I also made sure to run make ci to ensure that all existing tests pass as expected.

• Changelog entries added in the respective changelog/ directory (user-facing change, bug fix, security fix, update)
• Inspected CI output for image differences: /boot and /usr size, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.

resolves #1122

[tylerauerbeck]

I just added the necessary code to the existing pkg/api/api.go, but if this makes more sense to split out let me know and we can clean that up. Functionally though, this appears to be passing the sniff test and existing set of tests that I'd expect.