Import openstacksdk and dib into zuul tenant

This is a follow-on from I334edb00071031483f5a3e4b4715f773c0f261b1

In that change, we brought in the openstacksdk and dib projects into
the opendev tenant so jobs in https://review.opendev.org/696000 could
use them as required-projects.

Now, in change https://review.opendev.org/696486 we wish to use these
jobs in zuul/nodepool.  It currently fails with a rather cryptic

 This change depends on a change with an invalid configuration.

but I believe it is because these required-projects are not available.

Note this is not quite the same as
I5696ceecbab8a8b7f95c023ebb3f422d8acf3575 which we reverted with
I6d5e668bee9e37b96578f4f319db79fb30526682, since there we imported all
the jobs from openstacksdk, which led to 50+ errors about job
dependencies missing.  This only imports the projects for
required-projects.

I have removed the diskimage-builder from the job import section,
because I do not believe we use this any more.  This was when the
nodepool functional tests were defined in dib, but they have moved to
be defined inside nodepool.  nodepool doesn't run any of the jobs
defined by diskimage-builder (in fact the opposite, dib runs the
nodepool jobs).

Change-Id: I5673adce8f92994a17e8601f6a41a597f1ba7716

zuul/main.yaml

@@ -1689,6 +1689,8 @@
               - opendev/glean
               - opendev/jeepyb
               - opendev/zone-opendev.org
+              - openstack/diskimage-builder
+              - openstack/openstacksdk
               - openstack/requirements
               - recordsansible/ara
           # Include some projects with job config for cross-tenant
@@ -1696,7 +1698,6 @@
           - include: [job, secret, nodeset]
             projects:
               - opendev/system-config
-              - openstack/diskimage-builder
       github:
         untrusted-projects:
           # Don't load any configuration from these projects because we