This sets the PATH environment variable so that the binary installed to the
container image can be found by just its name. This makes it nicer to manually
provide a command by the container, so for example, now "docker run --rm -it
icinga/icingadb:dev icingadb --version" works. The binary is still installed
under the same path, so it can still be invoked using the same absolute path as
before.
Previously, we used https://github.com/Icinga/docker-icingadb to build and push
container images because Icinga DB did not support features necessary for
containerization, such as automatic schema import and configuration via
environment variables. These were handled by a specific entrypoint in that
repository. Now that these features are implemented directly in Icinga DB, the
repository is no longer needed, and container images can be built and pushed
directly from this repository.
