Write an openapi spec for the worker API and use `deepmap/oapi-codegen`
to generate scaffolding for the server-side using the `labstack/echo`
server.
Incidentally, echo by default returns the errors in the same format that
worker API always has:
{ "message": "..." }
The API itself is unchanged to make this change easier to understand. It
will be changed to better suit our needs in future commits.
RHEL requires the source code for dependencies to be included in the
srpm. The spec file already expects that, but we've only included the
vendored modules (i.e., the `vendor` directory) in the `rhel-8.2.`
branch. Move vendoring to master, so that we can build RHEL packages
from it as well.
This commit is the result of running `go mod vendor`, which includes the
vendored sources and updates go.mod and go.sum files.
Fedora requires the opposite: dependencies should not be vendored. The
spec file already ignores the `vendor` directory by default.
