Generate the certificate to be used for koji in make-certs.sh by
the same CA that also generates the composer and client certs.
Create a single certificate that uses the SubjectAltName (SAN)
extension to cover two domains: localhost, org.osbuild.koji.koji,
which previously was done via two separate certificates; this is
the legacy usage which stopped working with go 1.15 (see previous
commit). As a consequence the apache config is modified to use
only one virtual host with a ServerAlias directive.
Move the container directory, containing the container definitions
for all the test containers, to test/, where all the other test-
related files are located (with the exception of `Schutzbot`).
Use `test/build-container.sh` to build the container, instead of
replicating that in `test-integration.sh`.
